Document:

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                                                                 Exhibit A COVER

                           SECOND AMENDED AND RESTATED

                             STOCKHOLDERS AGREEMENT

                                      among

                                IFX CORPORATION,

                         UBS CAPITAL AMERICAS III, L.P.,

                                UBS CAPITAL LLC,

                    INTERNATIONAL TECHNOLOGY INVESTMENTS, LC,

                                JOEL EIDELSTEIN,

                                 MICHAEL SHALOM

                                       and

                             CASTY GRANTOR SUBTRUST

                             dated as of May 7, 2001
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                                                                       Exhibit A

                                 IFX CORPORATION

               SECOND AMENDED AND RESTATED STOCKHOLDERS AGREEMENT

         THIS SECOND AMENDED AND RESTATED STOCKHOLDERS AGREEMENT (this
"Agreement") is entered as of May 7, 2001, among IFX CORPORATION, a Delaware
corporation (the "Company"), UBS CAPITAL AMERICAS III, L.P., a Delaware limited
partnership, and UBS CAPITAL LLC, a Delaware limited liability company
(collectively, "UBS" and together with successors and assigns, the "Investor
Stockholders"), INTERNATIONAL TECHNOLOGY INVESTMENTS, LC, a Nevada limited
liability company ("ITI"), JOEL EIDELSTEIN, individually ("Eidelstein"), MICHEAL
SHALOM, individually ("Shalom"), and the CASTY GRANTOR SUBTRUST ("Casty"; ITI,
Shalom, Eidelstein and Casty, individually, a "Stockholder," and collectively,
the "Stockholders").

                                    RECITALS
                                    --------

         WHEREAS, the Company and the Investor Stockholders entered into that
certain IFX Corporation Preferred Stock Purchase Agreement, dated as of June 15,
2000, pursuant to which the Investor Stockholders purchased 2,030,869 shares of
Series A Preferred Stock; and

         WHEREAS, as a condition to and in consideration of the Investor
Stockholders' purchase of Series A Preferred Stock, the Company, the Investor
Stockholders and the Stockholders entered into that certain Amended and Restated
Stockholders Agreement dated as of June 15, 2000 (the "Existing Agreement"); and

         WHEREAS, the Company and the Investor Stockholders have entered into
the IFX Corporation Preferred Stock Purchase Agreement, dated March 13, 2001
(the "Stock Purchase Agreement"), pursuant to which the Investor Stockholders
will purchase newly issued shares of Series B Preferred Stock; and

         WHEREAS, as a condition to and in consideration of the Investor
Stockholders' purchase of Series B Preferred Stock, the Company, the Investor
Stockholders and the Stockholders have agreed to amend and restate the Existing
Agreement in the manner set forth below.

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
contained in this Agreement and for other valuable consideration the receipt and
sufficiency of which are hereby acknowledged, the parties hereto agree as
follows:

                                   ARTICLE I

                                   DEFINITIONS

         SECTION 1.1 Certain Defined Terms. As used herein, the following terms
shall have the following meanings:

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         "Affiliate" of a specified Person shall mean (a) any Person that
directly or indirectly, through one or more intermediaries, controls, is
controlled by, or is under common control with, such specified Person, (b) in
the case of a natural Person, such Person's spouse, parent or lineal descendant
(whether by blood or adoption and including stepchildren), a trust primarily for
the benefit of such Person and the foregoing, (c) in the case of a trust any
Person with whom the beneficiaries of the Trust are Affiliates, or (d) in the
case of UBS, (i) any company under the direct or indirect control of UBS AG (a
"UBS Group Company") and/or any partnership or unincorporated association under
the direct or indirect control of any UBS Group Company which includes, without
limiting the generality of the foregoing, any limited partnership the general
partner of which is a UBS Group Company and any limited liability company the
managing member of which is a UBS Group Company, and (ii) any alternative
investment vehicle formed by either of the foregoing, or any other entity (x) in
which UBS AG directly or indirectly owns at least 20% of the equity interests
and (y) is advised or managed (whether pursuant to contract, as general partner,
managing member or otherwise) by an entity in which UBS AG has a direct or
indirect equity interest. "Control" (including the terms "controlled by" and
"under common control with") shall mean the possession, directly or indirectly,
of the power to direct or cause the direction of the management policies of a
Person, whether through the ownership of voting securities, by contract or
credit arrangement, as trustee or executor, or otherwise.

         "Agent" has the meaning assigned to such term in Section 5.13.

         "as converted" has the meaning assigned to such term in Section 2.3.

         "beneficial owner" or "beneficially own" has the meaning given such
term in Rule 13d-3 under the Exchange Act and a Person's beneficial ownership of
Common Stock, Series A Preferred Stock or Series B Preferred Stock or other
Voting Securities of the Company shall be calculated in accordance with the
provisions of such Rule; provided, however, that for purposes of determining
beneficial ownership, (i) a Person shall be deemed to be the beneficial owner of
any security which may be acquired by such Person whether within 60 days or
thereafter, upon the conversion, exchange or exercise of any warrants, options,
rights or other securities and (ii) no Person shall be deemed to beneficially
own any security solely as a result of such Person's execution of this
Agreement.

         "Board" means the Board of Directors of the Company.

         "Bona Fide Purchaser" means, with respect to a proposed Transfer of
Equity Securities, any transferee of Equity Securities who or which (a) is not
an Affiliate of the Investor Stockholders and (b) has delivered a good faith
written offer to purchase Equity Securities.

         "Business Day" means any day that is not a Saturday, a Sunday or other
day on which banks are required or authorized by law to be closed in New York
City on the city of Miami, Florida.

         "Buyer" has the meaning assigned to such term in Section 3.6.

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         "Bylaws" means the Bylaws of the Company, as in effect on the date
hereof and as the same may be amended, supplemented or otherwise modified from
time to time in accordance with the terms thereof, the terms of the Certificate
and the terms of this Agreement.

         "Capital Stock" means, with respect to any Person at any time, any and
all shares, interests, participations or other equivalents (however designated,
whether voting or non-voting) of capital stock, partnership interests (whether
general or limited) or equivalent ownership interests in or issued by such
Person, and includes, in the case of the Company without limitation, any and all
shares of Common Stock, Series A Preferred Stock and Series B Preferred Stock.

         "Casty" has the meaning assigned to such term in the preamble.

         "Certificate" means the Certificate of Incorporation of the Company, as
in effect on the date hereof and as the same may be amended, supplemented or
otherwise modified from time to time in accordance with the terms thereof.

         "Closing" has the meaning assigned to such term in the Stock Purchase
Agreement.

         "Common Stock" means the common stock, par value $0.02 per share, of
the Company and any securities issued in respect thereof, or in substitution
therefor, in connection with any stock split, dividend or combination, or any
reclassification, recapitalization, merger, consolidation, exchange or other
similar reorganization.

         "control" (including the terms "controlled by" and "under common
control with"), with respect to the relationship between or among two or more
Persons, means the possession, directly or indirectly, of the power to direct or
cause the direction of the affairs or management of a Person, whether through
the ownership of voting securities, as trustee or executor, by contract or
otherwise.

         "Director" means any member of the Board.

         "Eidelstein" has the meaning assigned to such term in the preamble.

         "Equity Securities" means any and all shares of Capital Stock of the
Company, securities of the Company convertible into, or exchangeable or
exercisable for, such shares, and options, warrants or other rights to acquire
such shares.

         "Exchange Act" means the Securities Exchange Act of 1934, as amended,
or any similar federal statute and the rules and regulations promulgated
thereunder.

         "Family" means any spouse, lineal ancestor or descendant, brother or
sister

         "Holder" means an Investor Stockholder and any other holder of Equity
Securities who or which is a permitted transferee of an Investor Stockholders
pursuant to Section 3.1(c).

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         "Independent Director" has the meaning specified in Rule 4200(a)(14) of
the NASD listing standards, as in effect on the date hereof and as the same may
be amended or supplemented, or in any successor rule or regulation.

         "Independent Representative" has the meaning assigned to such term in
Section 2.1(a).

         "Investor Representative" has the meaning assigned to such term in
Section 2.1(a).

         "ITI" has the meaning assigned to such term in the preamble.

         "Joint Representative" has the meaning assigned to such term in Section
2.1(a).

         "NASD" means the National Association of Securities Dealers, Inc.

         "Offer" has the meaning assigned to such term in Section 3.5(a).

         "Offered Shares" has the meaning assigned to such term in Section
3.5(a).

         "Permitted Sales" means the Transfers permitted in the first and second
sentences of Section 3.3(a) and the first sentence of Section 3.4(a).

         "Person" means any individual, corporation, limited liability company,
limited or general partnership, joint venture, association, joint-stock company,
trust, unincorporated organization, government or any agency or political
subdivisions thereof or any other entity.

         "Preferred Stock" means the Series A Preferred Stock and Series B
Preferred Stock.

         "Proposed Transferee" has the meaning assigned to such term in Section
3.5(a).

         "Pro Rata Fraction" has the meaning assigned to such term in Section
3.5(c).

         "Qualified Public Offering" has the meaning assigned to such term in
the Stock Purchase Agreement.

         "Registration Rights Agreement" has the meaning assigned to such term
in the Stock Purchase Agreement.

         "Representatives" has the meaning assigned to such term in Section
2.1(b).

         "SEC" means the U.S. Securities and Exchange Commission or any other
federal agency then administering the federal securities laws.

         "Securities Act" has the meaning assigned to such term in Section 3.1.

         "Seller" has the meaning assigned to such term in Section 3.5(a).

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         "Series A Certificate of Designation" means the Amended and Restated
Series A Certificate of Designation, Number, Powers, Preferences and Relative,
Participating and Other Rights of Series A Convertible Preferred Stock of the
Company in the form attached as Exhibit I to the Stock Purchase Agreement.

         "Series B Certificate of Designation" means the Certificate of
Designation, Number, Powers, Preferences and Relative, Participating and Other
Rights of Series B Convertible Preferred Stock of the Company in the form
attached as Exhibit B to the Stock Purchase Agreement.

         "Series A Preferred Stock" means the Series A Preferred Stock, par
value $1.00 per share, of the Company.

         "Series B Preferred Stock" means the Series B Preferred Stock, par
value $1.00 per share, of the Company.

         "Shalom" has the meaning assigned to such term in the preamble.

         "Stockholders" has the meaning assigned to such term in the preamble.

         "Stock Purchase Agreement" has the meaning assigned to such term in the
recitals.

         "Transfer" means, directly or indirectly, to sell, transfer, assign,
pledge, encumber, hypothecate or similarly dispose of, either voluntarily or
involuntarily, or to enter into any contract, option or other arrangement or
understanding with respect to the sale, transfer, assignment, pledge,
encumbrance, hypothecation or similar disposition of, any shares of Equity
Securities beneficially owned by a Person or any interest in any shares of
Equity Securities beneficially owned by a Person.

         "UBS" means (i) UBS Capital Americas III, L.P., a Jersey, Channel
Island Islands limited partnership, (ii) UBS Capital LLC, a Delaware limited
liability Company, and (iii) any Affiliate of UBS, individually and
collectively.

         "Voting Securities" means, at any time, shares of any class of Equity
Securities of the Company which are then entitled to vote generally in the
election of Directors.

         SECTION 1.2 Other Definitional Provisions.

                  (a) The words "hereof", "herein" and "hereunder" and words of
         similar import when used in this Agreement shall refer to this
         Agreement as a whole and not to any particular provision of this
         Agreement, and Article and Section references are to this Agreement
         unless otherwise specified.

                  (b) The meanings given to terms defined herein shall be
         equally applicable to both the singular and plural forms of such terms.

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                                   ARTICLE II

                              CORPORATE GOVERNANCE

         SECTION 2.1 Board Representation.

                  (a) Effective on the date hereof, the Board shall be comprised
         of eight (8) Directors of whom: (i) three (3) shall be designees of the
         Investor Stockholders (the "Investor Representatives"), (ii) one (1)
         shall be the designee of ITI (the "ITI Representative"), (iii) one (1)
         shall be the designee of Casty (the "Casty Representative"), (iv) one
         (1) shall be jointly designated by ITI and Casty (the "Joint
         Representative") and (v) two (2) shall be Independent Directors
         acceptable to the Investor Stockholders, ITI and Casty (with such
         consents not to be unreasonably withheld or delayed) (the "Independent
         Representatives") and who, commencing with the election of Directors at
         the next annual meeting of stockholders, has been elected by the
         holders of a majority of the outstanding Voting Securities. The initial
         Investor Representatives shall be Charles W. Moore, Mark O. Lama and
         Charles Delaney, the initial ITI Representative shall be Michael
         Shalom, the initial Casty Representative shall be George Myers, the
         initial Joint Representative shall be Joel Eidelstein and the initial
         Independent Representatives shall be Burton Meyer and Patrick
         Delhougne. If, at any time, ITI and Casty are unable to agree upon the
         designation of the Joint Representative, the Joint Representative shall
         be designated by Jose Leiman. For purposes hereof, each of the two
         Series A Preferred Directors (as defined in the Series A Certificate of
         Designation) and the Series B Preferred Director (as defined in the
         Series B Certificate of Designation) shall each count as one of the
         three Investor Representatives.

                  (b) The Company shall take such action as may be required
         under applicable law (i) to cause the Board to consist of the number of
         Directors specified in clause (a), (ii) to include in the slate of
         nominees recommended by the Board the Investor Representatives, the ITI
         Representative, the Casty Representative, the Joint Representative and
         the Independent Representatives (collectively, the "Representatives"),
         and (iii) to cause the Representatives to be duly appointed in
         accordance with the foregoing and, in the case of the Investor
         Representatives, in accordance with the Series A Certificate of
         Designation or the Series B Certificate of Designation, as the case may
         be. The Company agrees to use its reasonable best efforts to cause the
         election of the Representatives to the Board, including nominating such
         individuals to be elected as Directors as provided herein.

                  (c) Each of the Investor Stockholders and the Stockholders
         agrees to vote, or act by written consent with respect to any Voting
         Securities beneficially owned by him or it, at each annual or special
         meeting of the stockholders of the Company at which Directors are to be
         elected or to take all actions by written consent in lieu of any such
         meeting as are necessary to cause the Representatives designated by the
         others in accordance with the terms of this Agreement to be elected to
         the Board and agrees to use his or its reasonable best efforts to cause
         the election of each such designee to the Board, including nominating
         such individuals to be elected as Directors.

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                  (d) In the event that a vacancy is created at any time by the
         death, disability, retirement, resignation or removal (with or without
         cause) of any Representative, the remaining Directors and the Company
         shall cause the vacancy created thereby to be filled by a new designee
         of the party or parties that designated such Director as soon as
         possible, who is designated in the manner specified in this Section
         2.1. Each of the Company, Investor Stockholders and the Stockholders
         hereby agrees to take, at any time and from time to time, all actions
         necessary to accomplish the same. Upon the written request of any party
         who is entitled to designated a Representative, each of the Investor
         Stockholders and Stockholders shall vote, or act by written consent
         with respect to all Voting Securities beneficially owned by him or it
         and otherwise take or cause to be taken all actions necessary to remove
         any Director designated by such party. Unless, any party who is
         entitled to designate a Representative shall otherwise request in
         writing, none of the others shall take any action to cause the removal
         of any Director designated by the former.

                  (e) Each of the Company, the Investor Stockholders and the
         Stockholders agrees not to take any action that would cause the number
         of Directors constituting the entire Board to be other than eight (8)
         without the written consent of each other party.

                  (f) The covenants and agreements set forth herein shall be
         subject to the fiduciary obligations of the Representatives now or
         hereafter serving on the Board and shall not prevent the
         Representatives now or hereafter serving on the Board from taking any
         action or refraining to take any action while acting in the capacity as
         a Director of the Company. The foregoing shall not limit the
         obligations of the Investor Stockholders, ITI and Casty in their
         capacity as stockholders of the Company hereunder.

                  (g) The Company has hired an executive search firm to help
         locate two new Independent Representatives who will serve as
         Independent Representative instead of Messrs. Meyer and Delhougne.
         After the Company has located such Independent Representatives
         acceptable to the Investor Stockholders, ITI and Casty, each of the
         Company, the Investor Stockholders and the Stockholders agree to take
         all actions reasonably necessary to cause (including all of such
         actions described in Section 2.1(c) hereof) Messrs. Meyer and Delhougne
         to be removed from the Board and to cause the newly designated
         Independent Representatives to be named as Directors of the Company.

         SECTION 2.2 Committees. The Company shall, except as provided below, by
amending its Bylaws or otherwise, establish and maintain a Compensation
Committee and an Audit Committee of the Board which satisfies the requirements
of this Section. The Compensation Committee shall consist of two (2) Directors,
both of whom shall be the Independent Representatives. The Audit Committee shall
consist of three (3) Directors, one (1) of whom shall be an Investor
Representative and two (2) of whom shall be Independent Representatives. The
Compensation Committee shall have responsibility for compensation matters
customarily addressed by compensation committees of similarly situated companies
and shall have the full power and authority of the Board with respect thereto,
except as limited by applicable law. The Audit Committee shall

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have responsibility for matters customarily addressed by audit committees of
similarly situated companies and shall have the full power and authority of the
Board with respect thereto, except as limited by applicable law. Notwithstanding
anything to the contrary herein, the Investor Stockholders and the Stockholders
acknowledge and agree that the composition of the Compensation and Audit
Committees must satisfy any applicable rules and regulations of the SEC and the
NASD as in effect from time to time.

         SECTION 2.3 Termination of Rights.

                  (a) Except with respect to the rights of the Investor
         Stockholders as provided in subparagraph (b) below, Sections 2.1 and
         2.2 shall terminate upon a Qualified Public Offering.

                  (b) The rights of the Investor Stockholders under Sections 2.1
         and 2.2 (and the corresponding obligations of the Stockholders) shall
         survive a Qualified Public Offering, provided that, at such time as the
         Investor Stockholders and their Affiliates shall cease to own in the
         aggregate at least 25% of the number of shares of Common Stock
         (determined with respect to the Preferred Stock and any other Equity
         Securities owned by the Investor Stockholders and their Affiliates that
         are convertible into (whether or not, in the case of the Preferred
         Stock, such Preferred Stock is then currently convertible at the option
         of the holder into Common Stock), or exchangeable or exercisable for
         Common Stock, on an as-converted, exchanged or exercised basis (any
         determination made in accordance with the foregoing shall hereinafter
         be referred to as "as converted")) that the Investor Stockholders and
         such Affiliates held as of the Closing (adjusted for stock splits,
         combinations, stock dividends and the like), the Investor Stockholders
         shall cease to have the right to designate Directors pursuant to
         Section 2.1 and members of the Compensation Committee and Audit
         Committee pursuant to Section 2.2 and all other rights of the Investor
         Stockholders or such Stockholder under this Article II shall terminate.

                                  ARTICLE III

                                    TRANSFERS

         SECTION 3.1 Investor Stockholder Transfers. Each Investor Stockholder
hereby agrees that it shall not Transfer any shares of its Equity Securities,
unless such Transfer is effected through (a) a public offering registered under
the Securities Act of 1933, as amended, and the rules and regulations
promulgated thereunder (the "Securities Act"), (b) sales made pursuant to Rule
144 under the Securities Act, or any successor provisions or (c) a Transfer
otherwise permitted hereunder and in compliance herewith. Any Equity Securities
Transferred pursuant to clause (a) or (b) shall no longer be subject to this
Agreement. Each transferee Holder under clause (c) shall agree in writing as a
condition to such Transfer, to be bound by all of the provisions of this
Agreement to the same extent as if such transferee were the transferring
Investor Stockholder, and all stock certificates representing shares transferred
to such transferee shall bear a legend providing notice of the restrictions
contained in this Agreement.

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         SECTION 3.2 Stockholder Transfers. Each Stockholder hereby agrees that
it shall not Transfer any shares of its Equity Securities, unless such Transfer
is effected through (a) a public offering registered under the Securities Act,
(b) sales made pursuant to Rule 144 under the Securities Act or any successor
provisions or (c) a Transfer otherwise permitted hereunder and in compliance
herewith. Any Equity Securities Transferred pursuant to clauses (a) or (b) shall
no longer be subject to this Agreement, except as provided herein. Each
transferee under clause (c) shall agree in writing as a condition to such
Transfer, to be bound by all of the provisions of this Agreement to the same
extent as if such transferee were the transferring Stockholder, and all stock
certificates representing shares transferred to such transferee shall bear a
legend providing notice of the restrictions contained in this Agreement.

         SECTION 3.3 Transfers by Eidelstein, ITI and Shalom.

                  (a) ITI and Shalom agree that neither such Stockholder nor any
         of its Affiliates shall Transfer more than 25,000 shares of Common
         Stock during any calendar quarter, in each case, without the written
         consent of the Investor Stockholders, which consent shall not be
         unreasonably withheld or delayed, or without compliance with Sections
         3.5 and 3.6; provided that Transfers by ITI and Shalom shall be
         aggregated for purposes of the foregoing. Eidelstein hereby agrees that
         neither he nor any of his Affiliates shall Transfer more than 25,000
         shares of Common Stock during any calendar quarter without the written
         consent of the Investor Stockholders, which consent shall not be
         unreasonably withheld or delayed, or without compliance with Sections
         3.5 and 3.6. Notwithstanding the foregoing, Eidelstein, ITI or Shalom
         may Transfer all or any of their Equity Securities (x) to any member of
         such Stockholder's Family or to any trust for the benefit of any such
         Family member of such Stockholder or to any other Affiliate (including,
         without limitation, the members of ITI), provided that any such
         transferee shall agree in writing with the Company and the Investor
         Stockholders as a condition to such Transfer, to be bound by all of the
         provisions of this Agreement to the same extent as if such transferee
         were such Stockholder, or (y) by will or the laws of descent and
         distribution; provided, however, in such event each such transferee
         shall be bound by all of the provisions of this Agreement to the same
         extent as if such transferee were such Stockholder; and provided,
         further, that each such transferee shall execute an irrevocable proxy
         appointing the original Stockholder (except in the case of death of the
         original Stockholder) transferring such shares as proxy to vote all
         such shares so transferred, such appointment shall be coupled with an
         interest, and all stock certificates representing such shares shall
         bear a legend providing notice of such appointment of proxy and the
         restrictions contained in this Agreement.

                  (b) The Transfer restrictions contained in Section 3.3(a)
         shall terminate upon the earlier of: (i) a Qualified Public Offering
         and (ii) the time at which the Investor Stockholders and the other
         Holders own less than 20% of the Common Stock (on an as converted
         basis) that the Investor Stockholders owned as of the Closing.

         SECTION 3.4 Transfers by Casty.

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                  (a) Casty agrees that neither it nor any of its Affiliates
         shall Transfer, during any calendar quarter, more than the number of
         Shares of Common Stock permitted under Rule 144(e) of the Securities
         Act measured as of the last day of such calendar quarter plus 50% of
         the number of Shares of Common Stock which were eligible for sale (but
         not sold under this Section 3.4(a)) during the preceding calendar
         quarters (beginning with the calendar quarter ending March 31, 2001),
         without the written consent of the Investor Stockholders, which consent
         shall not be unreasonably withheld or delayed, or without compliance
         with Sections 3.5 and 3.6. Notwithstanding the foregoing, Casty may
         Transfer all or any of his Equity Securities (x) to any member of such
         Stockholder's Family, to any trust for the benefit of any such Family
         member of such Stockholder or to any other Affiliate, provided that any
         such transferee shall agree in writing as a condition to such Transfer,
         to be bound by all of the provisions of this Agreement to the same
         extent as if such transferee were such Stockholder, or (y) by will or
         the laws of descent and distribution; provided, however, in such event
         each such transferee shall be bound by all of the provisions of this
         Agreement to the same extent as if such transferee were such
         Stockholder; and provided, further, that each such transferee shall
         execute an irrevocable proxy appointing Joel Eidelstein as proxy to
         vote all such shares so transferred, such appointment shall be coupled
         with an interest, and all stock certificates representing such shares
         shall bear a legend providing notice of such appointment of proxy and
         the restrictions contained in this Agreement.

                  (b) The Transfer restrictions contained in Section 3.4(a)
         shall terminate upon the earlier of: (i) a Qualified Public Offering
         and (ii) the time at which the Investor Stockholders and the other
         Holders own less than 20% of the Common Stock (on an as converted
         basis) that the Investor Stockholders owned as of the Closing.

         SECTION 3.5 Right of First Refusal on Certain Transfers.

                  (a) If at any time a Stockholder or any of his/its Affiliates,
         other than the Company, desires to Transfer all or any part of their
         Equity Securities (other than pursuant to Permitted Sales) to any
         Person (the "Proposed Transferee"), such Stockholder (the "Seller")
         shall, except as provided below, submit a written offer (the "Offer")
         to sell such Equity Securities (the "Offered Shares"), first to the
         Company, and second to the Holders, on the same terms and conditions on
         which the Seller proposes to sell such Offered Shares to the Proposed
         Transferee. The parties acknowledge and agree that any Transfer
         described in the last sentence of Sections 3.3(a) and 3.4(a) shall not
         be subject to the terms of this Section. The Offer shall disclose the
         identity of the Proposed Transferee, the Offered Shares proposed to be
         sold, the terms and conditions, including price, of the proposed sale,
         and any other material facts relating to the proposed sale. The Offer
         shall further state that the Company and the Holders may acquire, in
         accordance with the provisions of this Agreement, all or any portion of
         the Offered Shares for the price and upon the other terms and
         conditions, including deferred payment (if applicable), set forth
         therein.

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                  (b) Upon receipt of the Offer, if the Company desires to
         purchase all or any part of the Offered Shares, the Company shall
         communicate in writing its election to purchase to the Seller, which
         communication shall state the number of Offered Shares the Company
         desires to purchase and shall be given to the Seller in accordance with
         Section 5.4 below within thirty (30) days of the date the Offer was
         made. Such notice shall, when taken in conjunction with the Offer, be
         deemed to constitute a valid, legally binding and enforceable agreement
         for the sale to, and purchase by, the Company of the number of Offered
         Shares specified by the Company in such notice and on the terms of the
         Offer. Sales of the Offered Shares to be sold to the Company pursuant
         to this Section 3.5(b) shall be made at the offices of the Company on
         the 45th day following the date the Offer was made (or if such 45th day
         is not a Business Day, then on the next succeeding Business Day). Such
         sales shall be effected by the Seller's delivery to the Company of a
         certificate or certificates evidencing the Offered Shares to be
         purchased by it, duly endorsed for transfer to the Company, against
         payment to the Seller of the purchase price therefor by the Company.

                  (c) Each Holder shall, subject to the prior purchase right of
         the Company, have the absolute right to purchase that number of Offered
         Shares not purchased by the Company as shall be equal to the number of
         Offered Shares not purchased by the Company multiplied by a fraction,
         the numerator of which shall be the number of shares of Common Stock
         (determined on an as converted basis) then owned by such Holder and the
         denominator of which shall be the aggregate number of shares of Common
         Stock (determined on an as converted basis) then owned by all of the
         Holders. The amount of Offered Shares that each Holder is entitled to
         purchase under this Section 3.5(c) shall be referred to as its "Pro
         Rata Fraction." The Holders shall have a right of oversubscription such
         that if any Holder fails to accept the Offer as to its Pro Rata
         Fraction, the other Holders shall, among them, have the right to
         purchase up to the balance of the Offered Shares not so purchased. Such
         right of oversubscription may be exercised by a Holder by accepting the
         Offer as to more than its Pro Rata Fraction. If, as a result thereof,
         such oversubscriptions exceed the total number of Offered Shares
         available in respect of such oversubscription privilege, the
         oversubscribing Holders shall be cut back with respect to their
         oversubscriptions on a pro rata basis in accordance with their
         respective Pro Rata Fractions or as they may otherwise agree among
         themselves. If a Holder desires to purchase all or any portion of the
         Offered Shares, said Holder shall communicate in writing its election
         to purchase to the Seller and the Company, which communication shall
         state the number of Offered Shares said Holder desires to purchase and
         shall be given to the Seller in accordance with Section 5.4 below
         within thirty (30) days of the date the Offer was made. Such
         communication shall, when taken in conjunction with the Offer, be
         deemed to constitute a valid, legally binding and enforceable agreement
         for the sale and purchase of such Offered Shares (subject to the
         aforesaid limitations as to a Holder's right to purchase more than its
         Pro Rata Fraction) and on the terms of the Offer. Sales of the Offered
         Shares to be sold to purchasing Holders pursuant to this Section 3.5(c)
         shall be made at the offices of the Company on the later of (i) the
         45th day following the date the Offer was made (or if such later of (i)
         the 45th day is not a Business Day, then on the next succeeding
         Business Day) and (ii) the third Business Day following receipt of all
         material governmental or other consents in connection with such sale.
         Such sales shall be effected by the Seller's

                                       11
<PAGE>

         delivery to each purchasing Holder of a certificate or certificates
         evidencing the Offered Shares to be purchased by it, duly endorsed for
         transfer to such purchasing Holder, against payment to the Seller of
         the purchase price therefor by such purchasing Holder.

                  (d) If the Holders and the Company do not purchase in the
         aggregate all of the Offered Shares, the Offered Shares not so
         purchased may be sold by the Seller at any time within 90 days after
         the date the Offer was made, subject to the provisions of Section 3.6
         hereof. Any such sale shall be to the Proposed Transferee, at the price
         and upon the other terms and conditions specified in the Offer. Any
         Offered Shares not sold within such 90-day period shall continue to be
         subject to the requirements of a prior offer pursuant to this Section
         3.5. If Offered Shares are sold pursuant to this Section 3.5 to any
         purchaser who is not a party to this Agreement, the Offered Shares so
         sold shall no longer be subject to this Agreement.

                  (e) The provisions of this Section 3.5 shall terminate upon
         the earlier of: (i) a Qualified Public Offering and (ii) the time at
         which the Investor Stockholders and the other Holders own less than 20%
         of the Common Stock (on an as converted basis) that the Investor
         Stockholders owned as of the Closing.

         SECTION 3.6 Right of Participation in Sales by Stockholders.

                  (a) If at any time any of the Stockholders (the "Tag-Along
         Seller") desires to Transfer all or any part of the Equity Securities
         (other than pursuant to Permitted Sales) owned by such Tag-Along Seller
         to any Person other than Investor Stockholders (including the other
         Holders) (the "Buyer"), the Investor Stockholders shall, except as
         provided below, have the right to sell to the Buyer, as a condition to
         such sale by Tag-Along Seller, at the same price per share and on the
         same terms and conditions as involved in such sale by the Tag-Along
         Seller, a number of shares of Common Stock (on an as converted basis)
         equal to the number derived from multiplying the total number of shares
         of Common Stock (on an as converted basis) proposed to be sold by the
         Tag-Along Seller by a fraction, the numerator of which is the total
         number of shares of Common Stock (on an as converted basis) held by the
         Investor Stockholders and the denominator of which is the total number
         of shares of Common Stock (on an as converted basis) held by the
         Tag-Along Seller and the Investor Stockholders (including the other
         Holders). The parties acknowledge and agree that any Transfer described
         in the last sentence of Sections 3.3(a) and 3.4 (a) shall not be
         subject to the terms of this Section.

                  (b) Each Investor Stockholder wishing to so participate in any
         sale under this Section 3.6 shall notify the Tag-Along Seller in
         writing of such intention within twenty (20) days after the date of
         their receipt of the Offer.

                  (c) The Tag-Along Seller and each participating Investor
         Stockholder shall sell to the Buyer all, or at the option of the Buyer
         any part, of the Equity Securities proposed to be sold by them at the
         price and upon other terms and conditions contained in the Offer
         provided by the Tag-Along Seller under Section 3.5 above; provided,
         however, that any purchase of less than all of such Equity Securities
         by the Buyer shall be made from the Tag-Along Seller and each
         participating Investor

                                       12
<PAGE>

         Stockholder pro rata based upon the relative amount of the Equity
         Securities that the Tag-Along Seller and each participating Investor
         Stockholder is otherwise entitled to sell pursuant to Section 3.6(a).

                  (d) The provisions of this Section 3.6 shall terminate upon a
         Qualified Public Offering.

         SECTION 3.7 Right of Participation in Sales by Investor Stockholders.

                  (a) If at any time the Investor Stockholders desire to
         Transfer at least 40% of the Equity Securities owned in the aggregate
         by them and their Affiliates to any Person other than an Affiliate of
         the Investor Stockholders (the "Tag-Along Purchaser"), each of the
         other Stockholders, shall have the right to sell to the Tag-Along
         Purchaser, as a condition to such sale by the Investor Stockholders, at
         the price per share and on the terms and conditions applicable to the
         Common Stock set forth in the Tag-Along Purchaser's offer to the
         Investor Stockholders (the "Tag-Along Purchase Offer"), a number of
         shares of Common Stock equal to the number derived from multiplying the
         total number of shares of Common Stock (on an as converted basis)
         proposed to be sold by the Investor Stockholders by a fraction, the
         numerator of which is the total number of shares of Common Stock (on an
         as converted basis) held by such Stockholder and the denominator of
         which is the total number of shares of Common Stock (on an as converted
         basis) held by all Stockholders and the Investor Stockholders.

                  (b) Each Stockholder wishing to so participate in any sale
         under this Section 3.7 shall notify the Agent in writing of such
         intention within twenty (20) days after the date such Stockholder's
         receipt of the Tag-Along Purchase Offer.

                  (c) The Investor Stockholders and each participating
         Stockholder shall sell to the Tag-Along Purchaser all, or at the option
         of the Tag-Along Purchaser any part, of the Equity Securities proposed
         to be sold by them at the price per share and on the terms and
         conditions as set forth with respect to each class and series of
         Capital Stock in the Tag-Along Purchaser Offer; provided, however, that
         any purchase of less than all of such Equity Securities by the
         Tag-Along Purchaser shall be made from the Investor Stockholders and
         each participating Stockholder pro rata based upon the relative amount
         of the Equity Securities that the Investor Stockholder (including the
         other Holders) and each participating Stockholder is otherwise entitled
         to sell pursuant to Section 3.7(a).

                  (d) The provisions of this Section 3.7 shall terminate upon a
         Qualified Public Offering.

         SECTION 3.8 Drag-Along Rights.

                  (a) Subject to Section 3.8(c) hereof, if the Investor
         Stockholders (collectively, the "Drag-Along Transferor") approve a sale
         of (i) a majority of the outstanding shares of Common Stock on an as
         converted basis to a Bona Fide Purchaser or (ii) all or substantially
         all of the assets of the Company to a Bona Fide

                                       13
<PAGE>

         Purchaser (each an "Approved Sale"), whether by way of merger,
         consolidation, sale of stock or assets, or otherwise, all Stockholders
         shall consent to and raise no objections against the Approved Sale, and
         if the Approved Sale is structured as (A) a merger or consolidation of
         the Company or a subsidiary, or a sale of all or substantially all of
         the assets of the Company or a subsidiary, each Stockholder shall waive
         any dissenters rights, appraisal rights or similar rights in connection
         with such merger, consolidation or asset sale, or (B) a sale of a
         majority of the outstanding shares of Common Stock on an as converted
         basis the Stockholders shall agree to sell their respective
         proportionate percentages of the Common Stock on an as converted basis
         which are the subject of the Approved Sale, on the same terms and
         conditions as applicable to the Common Stock of the Drag-Along
         Transferor. The Stockholders shall take all actions reasonably
         requested by the Drag Along Transferor in connection with the
         consummation of the Approved Sale, including the execution of all
         agreements and such instruments and other actions requested by the Drag
         Along Transferor to provide the representations, warranties,
         indemnities, covenants, conditions, agreements, escrow agreements and
         other provisions and agreements relating to such Approved Sale;
         provided, however, that each participating Stockholder's liability
         under any such agreement or instrument shall be limited to his/her/its
         proportionate percentage of such liability (based on the number of
         shares of Common Stock on an as converted basis held by such
         Stockholder which are subject to the Approved Sale) and shall not
         exceed the proceeds received by such Stockholder. The Stockholders
         shall be permitted to sell their Equity Securities pursuant to an
         Approved Sale without complying with the provisions of Sections 3.1,
         3.2, 3.3, 3.4, 3.5, 3.6 and 3.7 of this Agreement.

                  (b) If the Company and/or the Drag-Along Transferor or their
         representatives, enter into any negotiation or transaction for which
         Regulation D under the Securities Act (or any similar rule or
         regulation then in effect) may be available with respect to such
         negotiation or transaction (including a merger, consolidation or other
         reorganization), each Stockholder who is not an accredited investor (as
         such term is defined in Rule 501 under the Securities Act) will, at the
         request of the Company or the Drag Along Transferor, appoint a
         purchaser representative (as such term is defined in Rule 501 under the
         Securities Act) reasonably acceptable to the Company and such Drag
         Along Transferor.

                  (c) At the closing of the Approved Sale, each of the
         Stockholders shall (a) execute any documents or instruments reasonably
         requested by the Bona Fide Purchaser, and (b) deliver to the Bona Fide
         Purchaser certificates for the Equity Securities, duly endorsed or
         accompanied by duly executed stock assignments separate from
         certificate, free and clear of all encumbrances (other than those
         created pursuant to this Agreement), against delivery by the Bona Fide
         Purchaser of the consideration (including a certified check for the
         cash portion of such consideration) for the total sales price of the
         Equity Securities being sold by such Stockholder.

                  (d) The provisions of this Section 3.8 shall terminate upon
         consummation of a Qualified Public Offering.

                                       14
<PAGE>

                                   ARTICLE IV

                         APPROVAL RIGHTS OF STOCKHOLDERS

         SECTION 4.1 Stockholder Approval Rights. The Company shall not (and the
Investor Stockholders shall not take any action to cause the Company to) take
any action to (i) enter into any transaction, or any agreement or understanding
with the Investor Stockholders or any Affiliate of the Investor Stockholders
(other than with respect to a Transfer of Equity Securities or as contemplated
by this Agreement, the Stock Purchase Agreement or the Transaction Documents (as
defined in the Stock Purchase Agreement)) or (ii) amend, modify, change or alter
the Company's Certificate of Incorporation or By-Laws or the Series A
Certificate of Designation or the Series B Certificate of Designation in a
manner adverse to the Company or holders of Common Stock, without the written
consent of the Stockholders holding a majority of the Common Stock, on an as
converted basis, held by all Stockholders which consent shall not be
unreasonably withheld or delayed.

                                   ARTICLE V

                                  MISCELLANEOUS

         SECTION 5.1 Termination. Except as otherwise provided herein, the
provisions of this Agreement shall terminate: (a) upon the agreement of all of
the parties hereto, (b) with respect to any of the Stockholders (other than
Eidelstein) and their respective permitted transferees referred to in the last
sentence of Section 3.3(x) or Section 3.4, as the case may be, when such
Stockholder together with its permitted transferees owns less than 1.25% of the
outstanding Common Stock (on an as converted basis) and (c) with respect to
Eidelstein and his permitted transferees referred to in the last sentence of
Section 3.3, when Eidelstein's employment with the Company is terminated.

         SECTION 5.2 Amendments and Waivers. Except as otherwise provided
herein, no modification, amendment or waiver of any provision of this Agreement
shall be effective against the Company or any other party unless such
modification, amendment or waiver is approved in writing by the Company, the
Agent, acting on behalf of the Investor Stockholders, and the Stockholders. The
failure of any party to enforce any of the provisions of this Agreement shall in
no way be construed as a waiver of such provisions and shall not affect the
right of such party thereafter to enforce each and every provision of this
Agreement in accordance with its terms.

         SECTION 5.3 Successors, Assigns and Transferees. This Agreement shall
bind and inure to the benefit of and be enforceable by the parties hereto and
their respective heirs, personal representatives, successors and permitted
assigns. This Agreement may not be assigned by any party hereto without the
prior written consent of the other parties, except as otherwise provided herein.

                                       15
<PAGE>

         SECTION 5.4 Notices. All notices required or permitted hereunder shall
be in writing and shall be deemed effectively given: (a) upon personal delivery
to the party to be notified; (b) when sent by confirmed facsimile if sent during
normal business hours of the recipient, if not, then on the next business day;
(c) five (5) days after having been sent by registered or certified mail, return
receipt requested, postage prepaid; or (d) one (1) business day after deposit
with a nationally recognized overnight courier, specifying next day delivery,
with written verification of receipt. All communications shall be sent, with
respect to the Company and the Investor Stockholders, to their respective
addresses specified in the Stock Purchase Agreement (or at such other address as
any such party may specify by like notice) and, with respect to any other party,
to the address of such party as shown in the stock record books of the Company
(or at such other address as any such party may specify to all of the above by
like notice).

         SECTION 5.5 Further Assurances. At any time or from time to time after
the date hereof, the parties agree to cooperate with each other, and at the
request of any other party, to execute and deliver any further instruments or
documents and to take all such further action as the other party may reasonably
request in order to evidence or effectuate the consummation of the transactions
contemplated hereby and otherwise to carry out the intent of the parties
hereunder.

         SECTION 5.6 Entire Agreement. Except as otherwise expressly set forth
herein, this document, the Stock Purchase Agreement and the Registration Rights
Agreement embody the complete agreement and understanding among the parties
hereto with respect to the subject matter hereof and supersede and preempt any
prior understandings, agreements or representations by or among the parties,
written or oral, that may have related to the subject matter hereof in any way.

         SECTION 5.7 Delays or Omissions. It is agreed that no delay or omission
to exercise any right, power or remedy accruing to any party, upon any breach,
default or noncompliance by another party under this Agreement, shall impair any
such right, power or remedy, nor shall it be construed to be a waiver of any
such breach, default or noncompliance, or any acquiescence therein, or of or in
any similar breach, default or noncompliance thereafter occurring. It is further
agreed that any waiver, permit, consent or approval of any kind or character on
the part of any party hereto of any breach, default or noncompliance under this
Agreement or any waiver on such party's part of any provisions or conditions of
this Agreement, must be in writing and shall be effective only to the extent
specifically set forth in such writing. All remedies, either under this
Agreement, by law, or otherwise afforded to any party, shall be cumulative and
not alternative.

         SECTION 5.8 Governing Law; Jurisdiction; Waiver of Jury Trial. This
Agreement shall be governed by and construed and enforced in accordance with the
internal laws of the State of New York without regard to the principles of
conflicts of law thereof. Each party hereto hereby irrevocably submits to the
nonexclusive jurisdiction of the courts of the state of New York and of the
United States of America sitting in the City of New York, Borough of Manhattan,
for the adjudication of any dispute hereunder or in connection herewith or with
any transaction contemplated hereby or discussed herein, and hereby irrevocably
waives, and agrees not to assert in any suit, action or proceeding,

                                       16
<PAGE>

any claim that it is not personally subject to the jurisdiction of any such
court, that the venue thereof may not be appropriate, that such suit, action or
proceeding is improper or that this Agreement or any of the documents referred
to in this Agreement may not be enforced in or by said courts, and each party
hereto irrevocably agrees that all claims with respect to such suit, action or
proceeding may be heard and determined in such a New York state or federal
court. Each party hereby irrevocably waives personal service of process and
consents to process being served in any such suit, action or proceeding by
mailing a copy thereof to such party in the manner provided in Section 12(b) of
the Stock Purchase Agreement and agrees that such service shall constitute good
and sufficient service of process and notice thereof. Nothing contained herein
shall be deemed to limit in any way any right to serve process in any manner
permitted by law. EACH PARTY HEREBY IRREVOCABLY WAIVES ANY RIGHT IT MAY HAVE,
AND AGREES NOT TO REQUEST, A JURY TRIAL FOR THE ADJUDICATION OF ANY DISPUTE
HEREUNDER OR IN CONNECTION HEREWITH OR ARISING OUT OF THIS AGREEMENT OR ANY
TRANSACTION CONTEMPLATED HEREBY.

         SECTION 5.9 Severability. Whenever possible, each provision of this
Agreement shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Agreement is held to be invalid,
illegal or unenforceable in any respect under any applicable law or rule in any
jurisdiction, such invalidity, illegality or unenforceability shall not affect
any other provision or any other jurisdiction, but this Agreement shall be
reformed, construed and enforced in such jurisdiction as if such invalid,
illegal or unenforceable provision had never been contained herein.

         SECTION 5.10 Enforcement. Each party hereto acknowledges that money
damages would not be an adequate remedy in the event that any of the covenants
or agreements in this Agreement are not performed in accordance with its terms,
and it is therefore agreed that in addition to and without limiting any other
remedy or right it may have, the non-breaching party will have the right to an
injunction, temporary restraining order or other equitable relief in any court
of competent jurisdiction enjoining any such breach and enforcing specifically
the terms and provisions hereof.

         SECTION 5.11 Titles and Subtitles. The titles of the sections and
subsections of this Agreement are for convenience of reference only and are not
to be considered in construing this Agreement

         SECTION 5.12 Legend. Each certificate evidencing any of the shares of
Equity Securities held by the parties hereto shall bear a legend substantially
as follows:

                  "THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO THE
                  TERMS AND CONDITIONS OF THE SECOND AMENDED AND RESTATED
                  STOCKHOLDERS AGREEMENT, DATED AS OF MAY __, 2001, AS THE SAME
                  MAY BE AMENDED, A COPY OF WHICH THE COMPANY WILL FURNISH TO
                  THE HOLDER OF THIS CERTIFICATE UPON REQUEST AND WITHOUT
                  CHARGE."

                                       17
<PAGE>

         SECTION 5.13 Appointment of Agent. Each of the Investor Stockholders
hereby irrevocably appoints UBS (the "Agent") to act as its true and lawful
agent and attorney-in-fact and representative with full power and authority in
its name, place and stead to act on its behalf for all purposes under this
Agreement. The foregoing power of attorney is hereby declared to be irrevocable
and coupled with an interest, and such appointment includes, among other powers,
the power and authority to exercise all rights and privileges, and to discharge
all obligations, of the Investor Stockholders under this Agreement, including:

                  (a) designating and removing the Investor Representatives and
         otherwise taking all actions required to be taken by the Investor
         Stockholders under Article II, including providing consents;

                  (b) providing consents to Transfers under Section 3.3;

                  (c) giving and receiving notices hereunder and service of
         process in any legal action or other proceedings arising out of or
         related to this Agreement and the transactions hereby; and

                  (d) amending or waiving the provisions of this Agreement.

Any instructions given by the Agent hereunder shall be validly given on behalf
of each of the Investor Stockholders, and the Company shall have the right to
rely thereon. UBS hereby accepts the appointment provided for in this Agreement
and agrees to be bound by the provisions of this Agreement. All decisions and
actions by the Agent shall be binding upon each of the Investor Stockholders and
no Investor Stockholders shall have the right to object, dissent, protest or
otherwise contest the same. The Company may conclusively rely upon any action
taken by the Agent hereunder.

         SECTION 5.14 Termination of Joint Venture Agreement. By its execution
hereof, each of the Company, ITI, Emerging Networks, Inc. and Casty confirms
that the Subscription and Joint Venture Agreement, dated as of November 23,
1998, as amended, by and among the Company, Emerging Networks, Inc., ITI and
Casty was terminated as of June 15, 2000.

         SECTION 5.15 Stockholder's Representation.

                  (a) Each of the Stockholders severally (and not jointly)
         represents and warrants that all of the Equity Securities owned by
         it/him and any of its/his Affiliates is set forth on Exhibit A hereto
         and that each such Stockholder or it/his Affiliate owns such Equity
         Securities listed opposite its/his/their name free and clear of all
         Encumbrances (as defined in the Stock Purchase Agreement) except with
         respect to Casty, an option to purchase 100,000 shares of the Common
         Stock owned by Casty at a price of $.625 per share has been issued to
         Burton Meyer, a copy of which is attached hereto as Exhibit B.

                                       18
<PAGE>

                  (b) Each of Shalom and ITI severally (and not jointly)
         represents and warrants that Shalom controls the voting and disposition
         rights on all shares of Equity Securities owned by ITI or any of ITI's
         Affiliates.

         SECTION 5.16 Counterparts; Facsimile Signatures. This Agreement may be
executed in any number of counterparts, each of which shall be an original, but
all of which together shall constitute one instrument. This Agreement may be
executed by facsimile signature(s).

[Remainder of Page Intentionally Left Blank]

                                       19
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have executed the SECOND AMENDED
AND RESTATED STOCKHOLDERS AGREEMENT as of the date set forth in the first
paragraph hereof.

                                        IFX CORPORATION

                                        By:   /s/ Joel Eidelstein
                                              -------------------
                                              Name: Joel Eidelstein
                                              Title: President

                                        UBS CAPITAL AMERICAS III, L.P.

                                        By:  UBS Capital Americas III, LLC

                                              By:      /s/ Mark O. Lama
                                              Name: Mark O. Lama
                                              Title: Principal

                                              By:      /s/ Marc A. Unger
                                              Name: Marc A. Unger
                                              Title: Chief Financial Officer

                                        UBS CAPITAL LLC

                                        By:      /s/ Mark O. Lama
                                        Name: Mark O. Lama
                                        Title: Chief Financial Officer

                                        By:      /s/ Marc A. Unger
                                        Name: Marc A. Unger
                                        Title: Chief Financial Officer

                                        NTERNATIONAL TECHNOLOGY
                                        INVESTMENTS, LC

                                        By:      /s/ Michael Shalom
                                                 ------------------
                                        Name: Michael Shalom
                                        Title: Manager

                                       20
<PAGE>

                                                     /s/ Joel Eidelstein
                                                     ---------------------------
                                                     Joel Eidelstein

                                                     /s/ Michael Shalom
                                                     Michael Shalom

                                                     CASTY GRANTOR SUBTRUST

                                                     By: /s/ Mary Myers
                                                          Name: Mary Myers
Title: Trustee

The provisions of Section 5.14 of
this Agreement are hereby acknowledged
and agreed to.

EMERGING NETWORKS, INC.

By:  /s/ Zalman Lekach
     ------------------------
     Name: Zalman Lekach
     Title: Vice President

                                       21<PAGE>

                                                                       Exhibit B

               AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT
               --------------------------------------------------

         THIS AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT (this
"Agreement") is entered into as of May 7, 2001, among IFX Corporation, a
Delaware corporation (the "Company"), UBS Capital Americas III, L.P., a Delaware
limited partnership, and UBS Capital LLC, a Delaware limited liability company,
(collectively "UBS" and together with their successors and assigns, the
"Investor Stockholders"), INTERNATIONAL TECHNOLOGY INVESTMENTS, LC, a Nevada
limited liability company ("ITI"), and the CASTY GRANTOR SUBTRUST ("Casty").

                                    RECITALS
                                    --------

         WHEREAS, the Company and the Investor Stockholders entered into that
certain IFX Corporation Preferred Stock Purchase Agreement, dated as of June 15,
2000, pursuant to which the Investor Stockholders purchased 2,030,869 shares of
Series A Convertible Preferred Stock, par value $1.00 per share, of the Company
("Series A Preferred Stock");

         WHEREAS, as a condition to and in consideration of the Investor
Stockholders' purchase of Series A Preferred Stock, the Company, the Investor
Stockholders, ITI and Casty entered into that certain Registration Rights
Agreement dated as of June 15, 2000 (the "Existing Agreement"); and

         WHEREAS, the Company and the Investor Stockholders have entered into
the IFX Corporation Preferred Stock Purchase Agreement, dated March 13, 2001
(the "Stock Purchase Agreement"), pursuant to which the Investor Stockholders
will purchase shares of newly issued Series B Convertible Preferred Stock, par
value $1.00 per share, of the Company ("Series B Preferred Stock");

         WHEREAS, as a condition to and in consideration of the Investor
Stockholders entering into the Stock Purchase Agreement, the Company, the
Investor Stockholders, ITI and Casty have agreed to amend and restate the
Existing Agreement in the manner set forth below.

         NOW THEREFORE, in consideration of the mutual covenants and agreements
contained in this Agreement and for other valuable consideration, the receipt
and sufficiency of which are hereby acknowledged, the parties hereto agree as
follows:

         1. Certain Definitions. As used herein, the following terms shall have
the following meanings:

         "Closing" has the meaning assigned to such term in the Stock Purchase
Agreement.

         "Commission" means the Securities and Exchange Commission or any other
federal agency then administering the federal securities laws.
<PAGE>

         "Common Shares" means shares of Common Stock held by ITI and Casty and
their permitted assigns under Section 13(b) or the Investor Stockholders.

         "Common Stock" means the common stock, par value $0.02 per share, of
the Company and any securities issued in respect thereof, or in substitution
therefor, in connection with any stock split, dividend or combination, or any
reclassification, recapitalization, merger, consolidation exchange or other
similar reorganization.

         "Conversion Shares" means shares of Common Stock issued or issuable
upon conversion of the Preferred Shares or any other Convertible Securities held
by the Investor Stockholders.

         "Convertible Securities" shall mean (i) any rights, options or warrants
to acquire Common Stock or any capital stock of the Company or any Subsidiary,
including the Preferred Shares, and (ii) any notes, debentures, shares of
preferred stock or other securities, options, warrants or rights, which are
convertible or exercisable into, or exchangeable for, Common Stock or any
capital stock of the Company or any Subsidiary.

         "Exchange Act" means the Securities Exchange Act of 1934, as amended,
or any similar federal statute, and the rules and regulations promulgated
thereunder.

         "Preferred Shares" shall mean the Company's Series A Preferred Stock
and Series B Preferred Stock.

         "Registration Expenses" means the expenses so described in Section 8.

         "Restricted Stock" means the Conversion Shares and Common Shares,
excluding Conversion Shares and Common Shares which have been (a) registered
under the Securities Act pursuant to an effective registration statement filed
thereunder and disposed of in accordance with the registration statement
covering them or (b) publicly sold pursuant to Rule 144 under the Securities
Act.

         "Securities Act" means the Securities Act of 1933, as amended, or any
similar federal statute, and the rules and regulations promulgated thereunder.

         "Selling Expenses" shall mean the expenses so described in Section 8.

         2. Restrictive Legend. Each certificate representing Preferred Shares,
Conversion Shares or Common Shares shall, except as otherwise provided in this
Section 2 or in Section 3, be stamped or otherwise imprinted with a legend
substantially in the following form:

            "THIS SECURITY HAS NOT BEEN REGISTERED UNDER
            THE SECURITIES ACT OF 1933 OR ANY STATE
            SECURITIES LAWS AND MAY NOT BE TRANSFERRED OR
            OTHERWISE DISPOSED OF UNLESS IT HAS BEEN
            REGISTERED UNDER SUCH ACT AND ALL SUCH
            APPLICABLE LAWS OR AN EXEMPTION FROM
            REGISTRATION IS AVAILABLE."

                                                                               2
<PAGE>

A certificate shall not bear such legend if in the opinion of counsel
satisfactory to the Company (it being agreed that each of Neal, Gerber &
Eisenberg and Kaye, Scholer, Fierman, Hays & Handler, LLP shall be satisfactory)
the securities represented thereby may be publicly sold without registration
under the Securities Act and any applicable state securities laws.

         3. Removal of Legend. Each certificate for Preferred Shares, Conversion
Shares or Common Shares transferred shall bear the legend set forth in Section
2, except that such certificate shall not bear such legend if (i) such transfer
is in accordance with the provisions of Rule 144 (or any other rule permitting
public sale without registration under the Securities Act) or (ii) in the
opinion of counsel satisfactory to the Company (it being agreed that either of
Neal, Gerber & Eisenberg or Kaye, Scholer, Fierman, Hays & Handler, LLP shall be
satisfactory) the transferee and any subsequent transferee would be entitled to
transfer such securities in a public sale without registration under the
Securities Act.

         4. Required Registration. (a) At any time after the earlier of (i) 180
days following the consummation of a Qualified Public Offering (as defined in
the Stock Purchase Agreement) and (ii) June 15, 2001, the Investor Stockholders
holding Restricted Stock constituting at least 66 2/3% of the total shares of
Restricted Stock held by Investor Stockholders then outstanding, ITI or Casty
may request the Company to register under the Securities Act all or any portion
of the shares of Restricted Stock held by such requesting holder or holders for
sale in the manner specified in such notice, provided that the shares of
Restricted Stock for which registration has been requested shall have a
reasonably anticipated aggregate price to the public which is at least
$15,000,000 (the "Minimum Offering Price"); provided further that neither ITI
nor Casty shall request such registration prior to a Qualified Public Offering
without the consent of UBS. The only securities which the Company shall be
required to register pursuant hereto shall be shares of Common Stock, provided,
however, that, in any underwritten public offering contemplated by this Section
4 or Sections 5 and 6, the holders of Preferred Shares shall be entitled to sell
such Preferred Shares to the underwriters for conversion and sale of the shares
of Common Stock issued upon conversion thereof. Notwithstanding anything to the
contrary contained herein, the Company shall not be required to file any
registration statement under this Section 4, within such period of time after
the effective date of any earlier registration statement relating to an
underwritten public offering (other than a registration statement on Form S-3 or
any successor thereto relating to the resale of securities of the Company
acquired in connection with an acquisition or similar transaction (each, an
"Acquisition Registration Statement")) as shall be determined in good faith by
the managing underwriter of an underwritten public offering, provided that such
time period shall not exceed 180 days.

         (b) Following receipt of any notice under this Section 4, the Company
shall immediately notify all holders of Restricted Stock from whom notice has
not been received and shall use its reasonable best efforts to register under
the Securities Act, for public sale in accordance with the method of disposition
specified in such notice from requesting holders, the number of shares of
Restricted Stock specified in such notice (and in all notices received by the
Company from other holders within 30 days after the giving of such notice by the
Company). If such method of disposition shall be an underwritten public
offering, the Company shall designate the underwriter(s) of such offering,
subject to the approval by the holders of a majority of the shares of Restricted
Stock proposed to be sold in such offering, including the approval of holders of
at least 66 2/3% of the shares of Restricted Stock proposed to be sold by
Investor Stockholders, to be sold in such offering (such approval not to be
unreasonably withheld or

                                                                               3
<PAGE>

delayed). If the managing underwriter advises the Company in writing that in
such underwriter's good faith determination the marketing factors require a
limitation of the amount of Restricted Stock to be underwritten in such
registration, the Company shall (to the extent that the managing underwriter
believes that such securities can be sold in such offering without having an
adverse effect upon the marketing of such offering) register in such
registration (i) first, the Restricted Stock proposed to be sold by the parties
participating in the demand registration of Restricted Stock under this Section
4, pro rata based upon the number of shares of Restricted Stock proposed to be
sold by such holders; and (ii) second securities held by the Company. The
Company shall be obligated to register Restricted Stock pursuant to this Section
4, in the case of registrations requested by each of the Investor Stockholders,
ITI and Casty on three occasions only, provided, however, that such obligation
shall be deemed satisfied only when a registration statement covering all shares
of Restricted Stock specified in demand notices delivered pursuant to Section
4(a), for sale in accordance with the method of disposition specified by the
requesting holders, shall have become effective and, if such method of
disposition is a firm commitment underwritten public offering, all such shares
designated in the notice shall have been sold pursuant thereto.

         (c) The Company shall, subject to Section 4(b), be entitled to include
in any registration statement referred to in this Section 4 for sale in
accordance with the method of disposition specified by the requesting holders,
shares of Common Stock to be sold by the Company for its own account.

         5. Incidental Registration. If the Company at any time (other than
pursuant to Section 4 or Section 6) proposes to register any of its securities
under the Securities Act for sale to the public, whether for its own account or
for the account of other security holders or both (except with respect to
registration statements on Forms S-4, S-8 or another form not available for
registering the Restricted Stock for sale to the public), each such time it will
give written notice to all holders of outstanding Restricted Stock of its
intention so to do. Upon the written request of any such holder, received by the
Company within 30 days after the giving of any such notice by the Company, to
register any of its Restricted Stock, the Company will use its reasonable best
efforts to cause the Restricted Stock as to which registration shall have been
so requested to be included in the securities to be covered by the registration
statement proposed to be filed by the Company, all to the extent requisite to
permit the sale or other disposition by the holder of such Restricted Stock so
registered. In the event that any registration pursuant to this Section 5 shall
be, in whole or in part, an underwritten public offering of Common Stock, and
the managing underwriter advises the Company in writing that in such
underwriter's good faith determination the marketing factors require a
limitation of the amount of Restricted Stock to be underwritten in such
registration then (a) if such registration is a primary registration on behalf
of the Company, the Company shall (to the extent that the managing underwriter
believes that such securities can be sold in such offering without having an
adverse effect upon the marketing of such offering) register in such
registration (i) first, the Company securities which the Company proposes to
sell in such registration, (ii) second, the Restricted Stock held by Investor
Stockholders which they propose to sell in such registration on a pro rata basis
based upon the number of shares of Restricted Stock owned by such holders, (iii)
third, Restricted Stock held by ITI and Casty which they propose to sell in such
registration on a pro rata basis based upon the number of shares of Restricted
Stock owned by such holders and (iv) fourth, securities held by other parties
eligible for inclusion in such registration statement on a pro rata basis based
upon the amount of securities held by them, and (b) if such registration is a
secondary registration, the

                                                                               4
<PAGE>

Company shall (to the extent that the managing underwriter believes that such
securities can be sold in such offering without having an adverse effect upon
the marketing of such offering) register in such registration (i) first, the
Restricted Stock held by Investor Stockholders which they propose to sell in
such registration on a pro rata basis based upon the number of shares of
Restricted Stock owned by such holders, (ii) second, the Restricted Stock held
by ITI and Casty which they propose to sell in such registration on a pro rata
basis based upon the number of shares of Restricted Stock owned by such holders
and (iii) third, the securities held by other parties eligible for inclusion in
such registration on a pro rata basis based upon the amount of securities held
by them. Notwithstanding the foregoing provisions, the Company may withdraw any
registration statement referred to in this Section 5, without thereby incurring
any liability to the holders of Restricted Stock other than for the payment of
Registration Expenses in accordance with Section 8.

         6. Registration on Form S-3. (a) Subject to the restrictions on
transfer set forth in Section 3.3 and 3.4 of the Stockholders Agreement (as
defined in the Stock Purchase Agreement), if at any time (i) one or more
Investor Stockholders, ITI or Casty requests that the Company file a
registration statement on Form S-3 or any successor thereto for a public
offering of all or any portion of the shares of Restricted Stock held by such
requesting holder or holders, the reasonably anticipated aggregate price to the
public of which would exceed $2,500,000, provided that the Restricted Stock for
which registration has been requested constitutes at least 10% of the total
shares of Restricted Stock then outstanding held by Investor Stockholders, if
such registration is requested by one or more Investor Stockholders, or at least
10% of the total shares of Restricted Stock then outstanding held by ITI or
Casty, as the case may be, if such registration is requested by ITI or Casty,
and (ii) the Company is a registrant entitled to use Form S-3 or any successor
thereto to register such shares, then the Company shall use its reasonable best
efforts to register under the Securities Act on Form S-3 or any successor
thereto, for public sale in accordance with the method of disposition specified
in such notice, the number of shares of Restricted Stock specified in such
notice. Whenever the Company is required by this Section 6(a) to use its
reasonable best efforts to effect the registration of Restricted Stock, each of
the procedures and requirements of Section 4 (including but not limited to the
requirement that the Company notify all holders of Restricted Stock from whom
notice has not been received and provide them with the opportunity to
participate in the offering) shall apply to such registration, provided,
however, that each of the Investor Stockholders (considered as a group), ITI and
Casty may only request and obtain two registrations on Form S-3 under this
Section in any calendar year, provided, further, that no request may be made by
a party under this Section 6(a) within 180 days after the effective date of any
other registration statement filed by the Company pursuant to this Section on
behalf of such party.

         (b) Notwithstanding Section 6(a) above, Casty may request, by written
notice, that the Company file a registration statement on Form S-3 or any
successor thereto for a public offering of all or any portion of the Restricted
Stock held by Casty (or any Affiliate thereof) and eligible for transfer
pursuant to the restrictions on transfer contained in the first sentence of
Section 3.4 of the Stockholders Agreement (the "Eligible Shares") and if the
Company is a registrant entitled to use Form S-3 or any successor thereto to
register such shares, then the Company shall use its reasonable best efforts to
register under the Securities Act on Form S-3 or any successor thereto, for
public sale the number of shares of Restricted Stock specified in such written
notice to the Company (not to exceed the number of Eligible Shares); provided,
however, that (i) any registration under this Section 6(b) shall be a
non-underwritten offering; (ii) Casty

                                                                               5
<PAGE>

shall only be entitled to request two registrations under this Section 6(b);
(iii) the Company shall only be obligated to effect one such registration during
any calendar year (which shall count as one of the two permitted in such
calendar year pursuant to Section 6(a)); and (iv) the Company shall not be
required to maintain the effectiveness of any such registration statement for
more than 60 days. Notwithstanding anything to the contrary contained herein,
the Company shall not be required to file any registration statement under this
Section 6(b): (x) within such period of time after the effective date of any
earlier registration statement relating to an underwritten public offering
(other than an Acquisition Registration Statement) as shall be determined in
good faith by the managing underwriter of an underwritten public offering,
provided that such time period shall not exceed 180 days or (y) if the Company
shall furnish to Casty a certificate signed by the President of the Company
stating that in the good faith judgment of the Board of Directors of the
Company, it would be seriously detrimental to the Company and its stockholders
for such registration to be effected at such time due to any pending material
financing, acquisition or corporate reorganization or other material corporate
development involving the Company or any of its subsidiaries.

         7. Registration Procedures. If and whenever the Company is required by
the provisions of Sections 4, 5 or 6 to use its reasonable best efforts to
effect the registration of any shares of Restricted Stock under the Securities
Act, the Company will, as expeditiously as possible:

         (a) prepare and file with the Commission a registration statement
(which, other than in the case of an underwritten public offering pursuant to
Section 4, may be on Form S-3 or any successor thereto if the Company is a
registrant entitled to use such Form) with respect to such securities and use
its reasonable best efforts to cause such registration statement to become and
remain effective for the period of the distribution contemplated thereby
(determined as hereinafter provided);

         (b) prepare and file with the Commission such amendments and
supplements to such registration statement and the prospectus used in connection
therewith as may be necessary to keep such registration statement effective for
the period specified in paragraph (a) above and comply with the provisions of
the Securities Act with respect to the disposition of all Restricted Stock
covered by such registration statement in accordance with the sellers' intended
method of disposition set forth in such registration statement for such period;

         (c) furnish to each seller of Restricted Stock and to each underwriter
such number of copies of the registration statement and the prospectus included
therein (including each preliminary prospectus) as such persons reasonably may
request in order to facilitate the public sale or other disposition of the
Restricted Stock covered by such registration statement;

         (d) use its reasonable best efforts to register or qualify the
Restricted Stock covered by such registration statement under the securities or
"blue sky" laws of such jurisdictions as the sellers of Restricted Stock or, in
the case of an underwritten public offering, the managing underwriter reasonably
shall request, provided, however, that the Company shall not for any such
purpose be required to qualify generally to transact business as a foreign
corporation in any jurisdiction where it is not so qualified or to consent to
general service of process in any such jurisdiction;

                                                                               6
<PAGE>

         (e) list the Restricted Stock covered by such registration statement
with any securities exchange on which the Common Stock of the Company is then
listed;

         (f) immediately notify each seller of Restricted Stock and each
underwriter under such registration statement, at any time when a prospectus
relating thereto is required to be delivered under the Securities Act, of the
happening of any event of which the Company has knowledge as a result of which
the prospectus contained in such registration statement, as then in effect,
includes an untrue statement of a material fact or omits to state a material
fact required to be stated therein or necessary to make the statements therein
not misleading in light of the circumstances then existing;

         (g) as soon as practicable upon the occurrence of any event
contemplated by Section 7(f), prepare and file a supplement or post-effective
amendment to such registration statement or the prospectus contained in such
registration statement, or any document incorporated therein by reference, or
file any other required document so that, as thereafter delivered to the
purchasers of the shares of Restricted Stock covered thereby, the prospectus
contained in such registration statement will not contain any untrue statement
of a material fact or omit to state a material fact necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading; provided, however, that the obligation to prepare and file
any such supplement, post-effective amendment or other document shall be
suspended (a "Suspension") if the Company shall furnish to the holders a
certificate signed by the President of the Company stating that in the good
faith judgment of the Board of Directors of the Company, it would be seriously
detrimental to the Company and its stockholders for such registration to be
effected at such time due to any pending material financing, acquisition or
corporate reorganization or other material corporate development involving the
Company or any of its subsidiaries; provided further, that the Company shall
only be permitted to effectuate one (1) Suspension in any twelve (12) month
period and any such suspension will be lifted by the Company as soon as
practicable and will not, in any event, extend for more than 60 days with
respect to any such specified event;

         (h) if the offering is underwritten and at the request of any seller of
Restricted Stock, use its reasonable best efforts to furnish on the date that
Restricted Stock is delivered to the underwriters for sale pursuant to such
registration: (i) an opinion dated such date of counsel representing the Company
for the purposes of such registration, addressed to the underwriters and to such
seller, stating that such registration statement has become effective under the
Securities Act and that (A) to the best knowledge of such counsel, no stop order
suspending the effectiveness thereof has been issued and no proceedings for that
purpose have been instituted or are pending or contemplated under the Securities
Act, (B) the registration statement, the related prospectus and each amendment
or supplement thereof comply as to form in all material respects with the
requirements of the Securities Act (except that such counsel need not express
any opinion as to financial statements contained therein) and (C) to such other
effects as reasonably may be requested by counsel for the underwriters or by
such seller or its counsel and (ii) a letter dated such date from the
independent public accountants retained by the Company, addressed to the
underwriters and to such seller, stating that they are independent public
accountants within the meaning of the Securities Act and that, in the opinion of
such accountants, the financial statements of the Company included in the
registration statement or the prospectus, or any amendment or supplement
thereof, comply as to form in all material respects with the applicable
accounting requirements of the Securities Act, and such letter shall
additionally cover such other financial matters (including information as to the
period ending no more than five business days

                                                                               7
<PAGE>

prior to the date of such letter) with respect to such registration as such
underwriters reasonably may request; and

         (i) make available for inspection by each seller of Restricted Stock,
any underwriter participating in any distribution pursuant to such registration
statement, and any attorney, accountant or other agent retained by such seller
or underwriter, all financial and other records, pertinent corporate documents
and properties of the Company, and cause the Company's officers, directors and
employees to supply all information reasonably requested by any such seller,
underwriter, attorney, accountant or agent in connection with such registration
statement.

         Upon receipt of any notice from the Company of any event of the kind
described in Section 7.3(f), each seller of Restricted Stock (x) promptly will
discontinue disposition of any shares of Restricted Stock pursuant to such
registration statement until such seller of Restricted Stock has received copies
of the supplemented or amended prospectus contemplated by Section 7(g) (it being
understood that such discontinuance shall be deemed a Suspension subject to the
limitations on Suspensions set forth in Section 7(g)), (y) thereafter, will
utilize and distribute only such supplemented or amended prospectus, and (z) if
so directed by the Company, will deliver to the Company all copies of the
prospectus covering such shares of Restricted Stock in such party's possession
at the time of receipt of such suspension notice.

         For purposes of Section 7(a) and 7(b), the period of distribution of
Restricted Stock in a firm commitment underwritten public offering shall be
deemed to extend until each underwriter has completed the distribution of all
securities purchased by it, and the period of distribution of Restricted Stock
in any other registration shall be deemed to extend until the earlier of the
sale of all Restricted Stock covered thereby and 180 days following
effectiveness of registration.

         In connection with each registration hereunder, each seller of
Restricted Stock will furnish to the Company in writing such information with
respect to itself and the proposed distribution by it as reasonably shall be
necessary in order to assure compliance with federal and applicable state
securities laws, and will notify the Company promptly upon the happening of any
event during the period any registration statement is effective that makes any
statement regarding such seller made in a registration statement or the
prospectus contained therein untrue in any material respect or which requires
the making of any changes in a registration statement or the prospectus
contained therein in order to make the statements therein regarding such seller,
in light of circumstances under which they were made, not misleading.

         In connection with each registration pursuant to Sections 4, 5 or 6
covering an underwritten public offering, the Company and each seller agree to
enter into a written agreement with the managing underwriter selected in the
manner herein provided in such form and containing such provisions as are
customary in the securities business for such an arrangement between such
underwriter and companies of the Company's size and investment stature.

         8. Expenses. All expenses incurred by the Company in complying with
Sections 4, 5 and 6, including, without limitation, all registration and filing
fees, printing expenses, fees and disbursements of counsel and independent
public accountants for the Company, fees and expenses (including counsel fees)
incurred in connection with complying with state securities or "blue sky" laws,
fees of the National Association of Securities Dealers, Inc., transfer taxes,
fees

                                                                               8
<PAGE>

of transfer agents and registrars, costs of insurance and reasonable fees and
disbursements of one counsel for the sellers of Restricted Stock, but excluding
any Selling Expenses, are called "Registration Expenses". If ITI and/or Casty
are the only parties (other than the Company) selling Restricted Stock pursuant
to a registration statement described herein, "Registration Expenses" shall not
include the fees and disbursements of counsel for such sellers of Restricted
Stock. All underwriting discounts and selling commissions applicable to the sale
of Restricted Stock are called "Selling Expenses".

         The Company will pay all Registration Expenses in connection with each
registration statement under Sections 4, 5 or 6.

         9. Indemnification and Contribution. (a) In the event of a registration
of any of the Restricted Stock under the Securities Act pursuant to Sections 4,
5 or 6, the Company will indemnify and hold harmless each seller of such
Restricted Stock thereunder, each underwriter of such Restricted Stock
thereunder and each of their respective officers, directors, employees,
partners, agents or other person, if any, who controls such seller or
underwriter within the meaning of the Securities Act, against any losses,
claims, damages or liabilities, joint or several, to which such seller,
underwriter or controlling person may become subject under the Securities Act or
otherwise, insofar as such losses, claims, damages or liabilities (or actions in
respect thereof) arise out of or are based upon any untrue statement or alleged
untrue statement of any material fact contained in any registration statement
under which such Restricted Stock was registered under the Securities Act
pursuant to Sections 4, 5 or 6, any preliminary prospectus or final prospectus
contained therein, or any amendment or supplement thereof, or arise out of or
are based upon the omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, and will reimburse each such seller, each such underwriter and each
such controlling person for any legal or other expenses reasonably incurred by
them in connection with investigating or defending any such loss, claim, damage,
liability or action, provided, however, that the Company will not be liable in
any such case if and to the extent that any such loss, claim, damage or
liability arises out of or is based upon an untrue statement or alleged untrue
statement or omission or alleged omission so made in conformity with information
furnished by any such seller, any such underwriter or any such controlling
person in writing specifically for use in such registration statement or
prospectus and, provided further, however, that the Company will not be liable
to any such person or entity with respect to any such untrue statement or
omission or alleged untrue statement or omission made in any preliminary
prospectus that is corrected in the final prospectus filed with the Commission
pursuant to Rule 424(b) promulgated under the Securities Act (or any amendment
or supplement to such prospectus) if the person asserting any such loss, claim,
damage or liability purchased securities but was not given a copy of the final
prospectus (as amended or supplemented) at or prior to the written confirmation
of the sale of such securities to such person in any case where such delivery of
the final prospectus (as amended or supplemented) is required by the Securities
Act, unless such failure to deliver the final prospectus (as amended or
supplemented) was a result of the Company's failure to provide such prospectus
(as amended or supplemented).

         (b) In the event of a registration of any of the Restricted Stock under
the Securities Act pursuant to Sections 4, 5 or 6, each seller of such
Restricted Stock thereunder, severally and not jointly, will indemnify and hold
harmless the Company, each person, if any, who controls the Company within the
meaning of the Securities Act, each officer of the Company who signs the

                                                                               9
<PAGE>

registration statement, each director of the Company, each underwriter and each
person who controls any underwriter within the meaning of the Securities Act,
against all losses, claims, damages or liabilities, joint or several, to which
the Company or such officer, director, underwriter or controlling person may
become subject under the Securities Act or otherwise, insofar as such losses,
claims, damages or liabilities (or actions in respect thereof) arise out of or
are based upon any untrue statement or alleged untrue statement of any material
fact contained in the registration statement under which such Restricted Stock
was registered under the Securities Act pursuant to Sections 4, 5 or 6, any
preliminary prospectus or final prospectus contained therein, or any amendment
or supplement thereof, or arise out of or are based upon the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, and will reimburse the
Company and each such officer, director, underwriter and controlling person for
any legal or other expenses reasonably incurred by them in connection with
investigating or defending any such loss, claim, damage, liability or action,
provided, however, that such seller will be liable hereunder in any such case if
and only to the extent that any such loss, claim, damage or liability arises out
of or is based upon an untrue statement or alleged untrue statement or omission
or alleged omission made in reliance upon and in conformity with information
pertaining to such seller, as such, furnished in writing to the Company by such
seller specifically for use in such registration statement or prospectus, and
provided, further, however, that the liability of each seller hereunder shall be
limited to the proportion of any such loss, claim, damage, liability or expense
which is equal to the proportion that the public offering price of the shares
sold by such seller under such registration statement bears to the total public
offering price of all securities sold thereunder, but not in any event to exceed
the net proceeds received by such seller from the sale of Restricted Stock
covered by such registration statement.

         (c) Promptly after receipt by an indemnified party hereunder of notice
of the commencement of any action, such indemnified party shall, if a claim in
respect thereof is to be made against the indemnifying party hereunder, notify
the indemnifying party in writing thereof, but the omission so to notify the
indemnifying party shall not relieve it from any liability which it may have to
such indemnified party other than under this Section 9 and shall only relieve it
from any liability which it may have to such indemnified party under this
Section 9 if and to the extent the indemnifying party is prejudiced by such
omission. In case any such action shall be brought against any indemnified party
and it shall notify the indemnifying party of the commencement thereof, the
indemnifying party shall be entitled to participate in and, to the extent it
shall wish, to assume and undertake the defense thereof with counsel
satisfactory to such indemnified party, and, after notice from the indemnifying
party to such indemnified party of its election so to assume and undertake the
defense thereof, the indemnifying party shall not be liable to such indemnified
party under this Section 9 for any legal expenses subsequently incurred by such
indemnified party in connection with the defense thereof other than reasonable
costs of investigation and of liaison with counsel so selected, provided,
however, that, if the defendants in any such action include both the indemnified
party and the indemnifying party and the indemnified party shall have reasonably
concluded, based on advice of counsel, that there may be reasonable defenses
available to it which are different from or additional to those available to the
indemnifying party or if the interests of the indemnified party reasonably may
be deemed to conflict with the interests of the indemnifying party, the
indemnified party shall have the right to select a separate

                                                                              10
<PAGE>

counsel and to assume such legal defenses and otherwise to participate in the
defense of such action, with the reasonable expenses and fees of such separate
counsel and other reasonable expenses related to such participation to be
reimbursed by the indemnifying party as incurred.

         (d) In order to provide for just and equitable contribution in
circumstances in which the indemnity agreement provided for in Sections 9(a) and
9(b) above is for any reason held to be unenforceable by the indemnified party
although applicable in accordance with its terms, the Company and each holder of
Restricted Stock exercising rights under this Agreement shall contribute to the
aggregate losses, claims, damages and liabilities of the nature contemplated by
such indemnity agreement incurred by the Company and such holder, (i) in such
proportion as is appropriate to reflect the relative fault of the Company on the
one hand and such holder on the other, in connection with the statements or
omissions which resulted in such losses, claims, damages or liabilities or (ii)
if the allocation provided by clause (i) above is not permitted by applicable
law, in such proportion as is appropriate to reflect not only the relative fault
of, but also the relative benefits to, the Company on the one hand and such
holder on the other, in connection with the statements or omissions which
resulted in such losses, claims, damages or liabilities, as well as any other
relevant equitable considerations. The relative benefits to the indemnifying
party and indemnified party shall be determined by reference to, among other
things, the gross proceeds received by the indemnifying party and indemnified
party in connection with the offering to which such losses, claims, damages or
liabilities relate. The relative fault of the indemnifying party and indemnified
party shall be determined by reference to, among other things, whether the
action in question, including any untrue or alleged untrue statement of a
material fact or omission or alleged omission to state a material fact, has been
made by, or relates to information supplied by, the indemnifying party or the
indemnified party, and the parties' relative intent, knowledge, access to
information and opportunity to correct or prevent such action. The parties
hereto agree that it would not be just or equitable if contribution pursuant to
this Section 9(d) were determined by pro rata allocation or by any other method
of allocation which does not take account of the equitable considerations
referred to in the immediately preceding sentence. Notwithstanding the
provisions of this Section 9(d), each holder of Restricted Stock exercising
rights under this Agreement shall not be required to contribute any amount in
excess of the amount of the gross proceeds to such holder from sales of the
Restricted Stock of such holder under a registration statement.

         Notwithstanding the foregoing, no person guilty of fraudulent
misrepresentation (within the meaning of Section 11(f) of the Securities Act)
shall be entitled to contribution from any person who was not guilty of such
fraudulent misrepresentation. For purposes of this Section 9(d), each person, if
any, who controls a holder of Restricted Stock within the meaning of Section 15
of the Securities Act shall have the same rights to contribution as such holder,
and each director of the Company, each officer of the Company who signed a
registration statement and each person, if any, who controls the Company within
the meaning of Section 15 of the Act shall have the same rights to contribution
as the Company.

         10. Changes in Common Stock or Preferred Shares. If, and as often as,
there is any change in the Common Stock or the Preferred Shares by way of a
stock split, stock dividend, combination or reclassification, or through a
merger, consolidation, reorganization or recapitalization, or by any other
means, appropriate adjustment shall be made in the provisions hereof so that the
rights and privileges granted hereby shall continue with respect to the Common
Stock or the Preferred Shares as so changed.

                                                                              11
<PAGE>

         11. Rule 144 Reporting. With a view to making available the benefits of
certain rules and regulations of the Commission which may at any time permit the
sale of the Restricted Stock to the public without registration, the Company
agrees to:

         (a) make and keep public information available, as those terms are
understood and defined in Rule 144 under the Securities Act;

         (b) use its reasonable best efforts to file with the Commission in a
timely manner all reports and other documents required of the Company under the
Securities Act and the Exchange Act; and

         (c) furnish to each holder of Restricted Stock forthwith upon request a
written statement by the Company as to its compliance with the reporting
requirements of such Rule 144 and of the Securities Act and the Exchange Act, a
copy of the most recent annual or quarterly report of the Company, and such
other reports and documents so filed by the Company as such holder may
reasonably request in availing itself of any rule or regulation of the
Commission allowing such holder to sell any Restricted Stock without
registration.

         12. Representations and Warranties of the Company. The Company
represents and warrants to the Investor Stockholders, ITI and Casty as follows:

         (a) The execution, delivery and performance of this Agreement by the
Company have been duly authorized by all requisite corporate action on its part
and will not violate any provision of law, any order of any court or other
agency of government, the Certificate of Incorporation or By-laws each, as
amended, of the Company or any provision of any indenture, agreement or other
instrument to which it or any or its properties or assets is bound, conflict
with, result in a breach of or constitute (with due notice or lapse of time or
both) a default under any such indenture, agreement or other instrument or
result in the creation or imposition of any lien, charge or encumbrance of any
nature whatsoever upon any of the properties or assets of the Company, except
where the foregoing would not reasonably be expected to have a material adverse
effect on the Company or its business.

         (b) This Agreement has been duly executed and delivered by the Company
and constitutes the legal, valid and binding obligation of the Company,
enforceable against the Company in accordance with its terms.

         13. Miscellaneous.

         (a) Except as otherwise provided herein, no modification, amendment or
waiver of any provision of this Agreement shall be effective against the Company
or any other party unless such modification, amendment or waiver is approved in
writing by the Company and the holders of at least 66 2/3% of the outstanding
shares of Restricted Stock held by each of the Investor Stockholders, ITI and
Casty, provided that any modification, amendment or waiver which would adversely
affect any party hereto in a manner which is different from the manner the other
parties hereto are affected shall also require the approval of such party. The
failure of any party to enforce any of the provisions of this Agreement shall in
no way be construed as a waiver of such provisions and shall not affect the
right of such party thereafter to enforce each and every provision of this
Agreement in accordance with its terms.

                                                                              12
<PAGE>

         (b) This Agreement shall bind and inure to the benefit of and be
enforceable by the parties hereto and their respective heirs, personal
representatives, successors and permitted assigns. This Agreement and the rights
of the parties hereunder may not be assigned by any party hereto without the
prior written consent of the other parties, except as otherwise provided herein.
The Investor Stockholders may assign their rights and obligations hereunder to a
transferee of Restricted Stock, provided that such transferees agree in writing
to be bound by the provisions of this Agreement. ITI and Casty may assign all or
any portion of their rights and obligations hereunder to a transferee of
Restricted Stock, provided that each such transferee of ITI and Casty and any
subsequent transferee shall, together with ITI or Casty, as the case may be, be
deemed one person for purposes of this Agreement, and any right or notice
hereunder on behalf of such person may only be delivered by ITI or by Casty and,
provided, further, that ITI or Casty, as the case may be, shall provide notice
of any such assignment to the other parties hereto, and any such transferee must
agree in writing to be bound by the provisions of this Agreement.

         (c) All notices required or permitted hereunder shall be in writing and
shall be deemed effectively given: (i) upon personal delivery to the party to be
notified; (ii) when sent by confirmed facsimile if sent during normal business
hours of the recipient, if not, then on the next business day; (iii) five days
after having been sent by registered or certified mail, return receipt
requested, postage prepaid; or (iv) one business day after deposit with a
nationally recognized overnight courier, specifying next day delivery, with
written verification of receipt. All communications shall be sent, with respect
to the Company and the Investor Stockholders, to their respective addresses
specified in the Stock Purchase Agreement (or at such other address as any such
party may specify by like notice) and, with respect to any other party, to the
address of such party as shown in the stock record books of the Company (or at
such other address as any such party may specify to all of the above by like
notice).

         (d) Except as otherwise expressly set forth herein, this document, the
Stock Purchase Agreement, the Certificate (as defined in the Stock Purchase
Agreement) and the Stockholders Agreement embody the complete agreement and
understanding among the parties hereto with respect to the subject matter hereof
and supersede and preempt any prior understandings, agreements or
representations by or among the parties, written or oral, that may have related
to the subject matter hereof in any way.

         (e) This Agreement shall be governed by and construed and enforced in
accordance with the internal laws of the State of New York without regard to the
principles of conflicts of law thereof. Each party hereto hereby irrevocably
submits to the nonexclusive jurisdiction of the courts of the state of New York
and of the United States of America sitting in the City of New York, Borough of
Manhattan, for the adjudication of any dispute hereunder or in connection
herewith or with any transaction contemplated hereby or discussed herein, and
hereby irrevocably waives, and agrees not to assert in any suit, action or
proceeding, any claim that it is not personally subject to the jurisdiction of
any such court, that the venue thereof may not be appropriate, that such suit,
action or proceeding is improper or that this Agreement or any of the documents
referred to in this Agreement may not be enforced in or by said courts, and each
party hereto irrevocably agrees that all claims with respect to such suit,
action or proceeding may be heard and determined in such a New York state or
federal court. Each party hereby irrevocably waives personal service of process
and consents to process being served in any such suit, action or proceeding by
mailing a copy thereof to such party in the manner provided in Section 12(b) of
the Stock Purchase Agreement and agrees that such service shall constitute good
and sufficient

                                                                              13
<PAGE>

service of process and notice thereof. Nothing contained herein shall be deemed
to limit in any way any right to serve process in any manner permitted by law.
EACH PARTY HEREBY IRREVOCABLY WAIVES ANY RIGHT IT MAY HAVE, AND AGREES NOT TO
REQUEST, A JURY TRIAL FOR THE ADJUDICATION OF ANY DISPUTE HEREUNDER OR IN
CONNECTION HEREWITH OR ARISING OUT OF THIS AGREEMENT OR ANY TRANSACTION
CONTEMPLATED HEREBY.

         (f) The obligations of the Company to register shares of Restricted
Stock under Section 4, 5 or 6 shall terminate at the time at which all
Restricted Securities are eligible for resale pursuant to Rule 144(k) under the
Securities Act.

         (g) If requested in writing by the Company and the underwriters for an
underwritten public offering of securities of the Company, each holder of
Restricted Stock who is a party to this Agreement shall agree not to sell
publicly any shares of Restricted Stock or any other shares of Common Stock
(other than shares of Restricted Stock or other shares of Common Stock being
registered in such offering), without the consent of the Company and such
underwriters, for such period requested by the underwriters (not to exceed 180
days) following the effective date of the registration statement relating to the
Qualified Public Offering (as defined in the Stock Purchase Agreement) or 90
days following the effective date of a registration statement relating to any
other offering; provided, however, that all persons entitled to registration
rights with respect to shares of Common Stock who are not parties to this
Agreement, all persons holding 5% or more of the capital stock of the Company on
a fully diluted basis and all executive officers and directors of the Company
shall also have agreed not to sell publicly their Common Stock under the
circumstances and pursuant to the terms set forth in this Section 13(g).

         (h) Notwithstanding the provisions of Section 7(a), the Company's
obligation to file a registration statement, or cause such registration
statement to become and remain effective, shall be suspended for a period not to
exceed 90 days in any 12-month period if the Company shall furnish to the
holders a certificate signed by the President of the Company stating that in the
good faith judgment of the Board of Directors of the Company, it would be
seriously detrimental to the Company and its stockholders for such registration
to be effected at such time due to any pending material financing, acquisition
or corporate reorganization or other material corporate development involving
the Company or any of its subsidiaries; provided, however, that any suspension
effectuated by the Company under this Section 13(h) shall be deemed a Suspension
subject to the limitation on the number of Suspensions permitted in any twelve
month period under Section 7(g) hereof.

         (i) The Company shall not grant to any third party any registration
rights more favorable than or inconsistent with any of those contained herein,
so long as any of the registration rights under this Agreement remains in
effect.

         (j) Whenever possible, each provision of this Agreement shall be
interpreted in such manner as to be effective and valid under applicable law,
but if any provision of this Agreement is held to be invalid, illegal or
unenforceable in any respect under any applicable law or rule in any
jurisdiction, such invalidity, illegality or unenforceability shall not affect
any other provision or any other jurisdiction, but this Agreement shall be
reformed, construed and enforced in such jurisdiction as if such invalid,
illegal or unenforceable provision had never been contained herein.

                                                                              14
<PAGE>

     (k) The titles of the sections and subsections of this Agreement are for
convenience of reference only and are not to be considered in construing this
Agreement.

     (l) This Agreement may be executed in any number of counterparts, each of
which shall be an original, but all of which together shall constitute one
instrument. This Agreement may be executed by facsimile signature(s).

                                                                              15
<PAGE>

         IN WITNESS WHEREOF, the parties have executed this AMENDED AND RESTATED
REGISTRATION RIGHTS AGREEMENT as of the date set forth in the first paragraph
hereof.

                                              IFX CORPORATION

                                              By: /s/ Joel Eidelstein
                                                  Name: Joel Eidelstein
                                                  Title:

                                              UBS CAPITAL AMERICAS III, L.P
                                              By:  UBS Capital Americas III, LLC

                                              By: /s/ Mark O. Lama
                                                  Name: Mark O. Lama
                                                  Title: Principal

                                              By: /s/ Marc A. Unger
                                                  Name: Marc A. Unger
                                                  Title: Chief Financial Officer

                                              UBS CAPITAL LLC

                                              By: /s/ Mark O. Lama
                                                  Name: Mark O. Lama
                                                  Title: Attorney-in-fact

                                              By: /s/ Marc A. Unger
                                                  Name: Marc A. Unger
                                                  Title: Attorney-in-fact

                                              INTERNATIONAL TECHNOLOGIES
                                              INVESTMENTS, LLC

                                              By: /s/ Michael Shalom
                                                  Name: Michael Shalom
                                                  Title: Manager

                                              CASTY GRANTOR SUBTRUST

                                              By: /s/ Mary Myers
                                                  Name: Mary Myers
                                                  Title: Trustee

                                                                              16

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