<PAGE>   1


                                                                    EXHIBIT 4.18


                                   VERIO INC.

                                -----------------


                     10-5/8% SENIOR NOTES DUE 2009, SERIES B


CUSIP No.                                                             $
          ----------
No.
    -----------

               VERIO INC., a corporation incorporated under the laws of the
State of Delaware (herein called the "Company," which term includes any
successor corporation under this Indenture hereinafter referred to), for value
received, hereby promises to pay to ___________ or registered assigns, the
principal sum of _______________ Dollars on November 15, 2009, at the office or
agency of the Company referred to below, and to pay interest thereon on May 15
and November 15 (each, an "Interest Payment Date"), of each year, commencing on
May 15, 2000, accruing from the Issue Date or from the most recent Interest
Payment Date to which interest has been paid or duly provided for, at the rate
of 10-5/8% per annum, until the principal hereof is paid or duly provided for.
Interest shall be computed on the basis of a 360-day year of twelve 30-day
months.

               The interest so payable, and punctually paid or duly provided
for, on any Interest Payment Date will, as provided in the Indenture referred to
on the reverse hereof, be paid to the person in whose name this Note (or one or
more Predecessor Notes) is registered at the close of business on May 1 and
November 1 (each, a "Regular Record Date"), whether or not a Business Day, as
the case may be, next preceding such Interest Payment Date. Any such interest
not so punctually paid, or duly provided for, and interest on such defaulted
interest at the then applicable interest rate borne by the Notes, to the extent
lawful, shall forthwith cease to be payable to the Holder on such Regular Record
Date, and may be paid to the person in whose name this Note (or one or more
Predecessor Notes) is registered at the close of business on a Special Record
Date for the payment of such defaulted interest to be fixed by the Trustee,
notice of which shall be given to Holders of Notes not less than 10 days prior
to such Special Record Date, or may be paid at any time in any other lawful
manner not inconsistent with the requirements of any securities exchange on
which the Notes may be listed, and upon such notice as may be required by such
exchange, all as more fully provided in such Indenture.

               Payment of the principal of, premium, if any, and interest on
this Note will be made at the office or agency of the Company maintained for
that purpose in the Borough of Manhattan in The City of New York, State of New
York, or at such other office or agency of the Company as may be maintained for
such purpose, in such coin or currency of the United


                                     A-2-1


<PAGE>   2


States of America as at the time of payment is legal tender for payment of
public and private debts; provided, however, that payment of interest may be
made at the option of the Company by check mailed to the address of the person
entitled thereto as such address shall appear on the Note Register.

               Reference is hereby made to the further provisions of this Note
set forth on the reverse hereof.

               Unless the certificate of authentication hereon has been duly
executed by the Trustee referred to on the reverse hereof by manual signature,
this Note shall not be entitled to any benefit under the Indenture, or be valid
or obligatory for any purpose.

                  [Remainder of Page Intentionally Left Blank]


                                     A-2-2


<PAGE>   3


               IN WITNESS WHEREOF, the Company has caused this instrument to be
duly executed.

Dated:                           VERIO INC.


                                 By:
                                    --------------------------------------------
                                    Name:
                                    Title:


                                 By:
                                    --------------------------------------------
                                    Name:
                                    Title:


                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION


               This is one of the 10-5/8% Senior Notes due 2009, Series B,
referred to in the within-mentioned Indenture.

                                 U.S. BANK TRUST NATIONAL
                                      ASSOCIATION, as Trustee


                                 By:
                                    --------------------------------------------
                                    Authorized Signatory


                                     A-2-3


<PAGE>   4


                                [REVERSE OF NOTE]


               1. Indenture. This Note is one of a duly authorized issue of
Notes of the Company designated as its 10-5/8% Senior Notes due 2009, Series B
(herein called the "Initial Notes"). The Notes are limited (except as otherwise
provided in the Indenture referred to below) in aggregate principal amount to
$400,000,000, which may be issued under an indenture (herein called the
"Indenture") dated as of November 19, 1999, by and between the Company and U.S.
Bank Trust National Association, as trustee (herein called the "Trustee," which
term includes any successor Trustee under the Indenture), to which Indenture and
all indentures supplemental thereto reference is hereby made for a statement of
the respective rights, limitations of rights, duties, obligations and immunities
thereunder of the Company, the Trustee and the Holders of the Notes, and of the
terms upon which the Notes are, and are to be, authenticated and delivered. The
Notes include the Initial Notes, the Private Exchange Notes and the Unrestricted
Notes (including the Exchange Notes referred to below), issued in exchange for
the Initial Notes pursuant to the Registration Rights Agreement. The Initial
Notes and the Unrestricted Notes are treated as a single class of securities
under the Indenture.

               All capitalized terms used in this Note which are defined in the
Indenture and not otherwise defined herein shall have the meanings assigned to
them in the Indenture.

               The terms of the Notes include those stated in the Indenture and
those made part of the Indenture by reference to the Trust Indenture Act of 1939
(15 U.S.C. Sections 77aaa-77bbbb) (the "TIA"), as in effect on the date of the
Indenture. Notwithstanding anything to the contrary herein, the Notes are
subject to all such terms, and Holders of Notes are referred to the Indenture
and the TIA for a statement of such terms.

               No reference herein to the Indenture and no provisions of this
Note or of the Indenture shall alter or impair the obligation of the Company,
which is absolute and unconditional, to pay the principal of, premium, if any,
and interest on this Note at the times, place, and rate, and in the coin or
currency, herein prescribed.

               2. Redemption. The Notes will be redeemable, at the option of the
Company, in whole or in part, on or after November 15, 2004 upon not less than
30 nor more than 60 days' written notice at the redemption prices (expressed as
percentages of principal amount) set forth below, plus accrued and unpaid
interest thereon, if any, to the applicable redemption date, if redeemed during
the twelve-month period beginning on November 15 of each of the years indicated
below:


                                     A-2-4


<PAGE>   5

<TABLE>
<CAPTION>
   Year        Percentage
   ----        ----------
<S>             <C>
2004 .....      105.313%
2005 .....      103.542%
2006 .....      101.771%
2007 .....      100.000%
</TABLE>

               Notwithstanding the foregoing, in the event that after the Issue
Date and prior to November 15, 2002 the Company issues, in one or more
transactions, Capital Stock (other than Disqualified Stock) of the Company to
one or more Strategic Equity Investors or in any Equity Offering (an "Equity
Sale"), the Company may redeem, at its option, up to a maximum of 35% of the
initially Outstanding aggregate principal amount of Notes from the net proceeds
thereof at a redemption price equal to 110.625% of the principal amount of the
Notes, together with accrued and unpaid interest to the date of redemption;
provided that not less than $260.0 million aggregate principal amount of Notes
is Outstanding following such redemption. Any such redemption may only be
effected once and must be effected upon not less than 30 nor more than 60 days'
notice given within 180 days after such Equity Sale.

               3. Offers to Purchase. Sections 10.10 and 10.15 of the Indenture
provide that upon the occurrence of a Change of Control and following certain
Asset Sales, and subject to certain conditions and limitations contained
therein, the Company shall make an offer to purchase all or a portion of the
Notes in accordance with the procedures set forth in the Indenture.

               4. Defaults and Remedies. If an Event of Default occurs and is
continuing, the principal of all of the Outstanding Notes, plus all accrued and
unpaid interest, if any, to and including the date the Notes are paid, may be
declared due and payable in the manner and with the effect provided in this
Indenture.

               5. Defeasance. The Indenture contains provisions (which
provisions apply to this Note) for defeasance at any time of (a) the entire
indebtedness of the Company on this Note and (b) certain restrictive covenants
and related Defaults and Events of Default, in each case upon compliance by the
Company with certain conditions set forth therein.

               6. Amendments and Waivers. The Indenture permits, with certain
exceptions as provided therein, the amendment thereof and the modification of
the rights and obligations of the Company and the rights of the Holders under
the Indenture at any time by the Company and the Trustee with the consent of the
Holders of not less than a majority in aggregate principal amount of the Notes
at the time Outstanding. The Indenture also contains provisions permitting the
Holders of specified percentages in aggregate principal amount of the Notes at
the time Outstanding, on behalf of the Holders of all the Notes, to waive
compliance by the Company with certain provisions of the Indenture and certain
past Defaults under the Indenture and this Note and their consequences. Any such
consent or waiver by or on behalf of the Holder of this Note shall be conclusive
and binding upon such Holder and upon all future


                                     A-2-5


<PAGE>   6


Holders of this Note and of any Note issued upon the registration of transfer
hereof or in exchange herefor or in lieu hereof whether or not notation of such
consent or waiver is made upon this Note.

               7. Denominations, Transfer and Exchange. The Notes are issuable
only in registered form without coupons in denominations of $1,000 and any
integral multiple thereof. As provided in this Indenture and subject to certain
limitations therein set forth, the Notes are exchangeable for a like aggregate
principal amount of Notes of a different authorized denomination, as requested
by the Holder surrendering the same.

               As provided in the Indenture and subject to certain limitations
therein set forth, the transfer of this Note is registrable on the Note Register
of the Company, upon surrender of this Note for registration of transfer at the
office or agency of the Company maintained for such purpose in the Borough of
Manhattan in The City of New York, State of New York, or at such other office or
agency of the Company as may be maintained for such purpose, duly endorsed by,
or accompanied by a written instrument of transfer in form satisfactory to the
Company and the Registrar duly executed by, the Holder hereof or his attorney
duly authorized in writing, and thereupon one or more new Notes, of authorized
denominations and for the same aggregate principal amount, will be issued to the
designated transferee or transferees.

               No service charge shall be made for any registration of transfer
or exchange or redemption of Notes, but the Company may require payment of a sum
sufficient to cover any tax or other governmental charge payable in connection
therewith.

               8. Persons Deemed Owners. Prior to and at the time of due
presentment of this Note for registration of transfer, the Company, the Trustee
and any agent of the Company or the Trustee may treat the person in whose name
this Note is registered as the owner hereof for all purposes, whether or not
this Note shall be overdue, and neither the Company, the Trustee nor any agent
shall be affected by notice to the contrary.

               9. GOVERNING LAW. THE INDENTURE, THIS NOTE AND ANY GUARANTEE SET
FORTH BELOW SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF
THE STATE OF NEW YORK WITHOUT GIVING EFFECT TO PRINCIPLES OF CONFLICTS OF LAW.

               The Company will furnish to any Holder of a Note upon written
request and without charge a copy of this Indenture. Requests may be made to:
Verio Inc., 8005 South Chester Street, Suite 200, Englewood, Colorado 80112.


                                     A-2-6


<PAGE>   7


                                 ASSIGNMENT FORM


If you the holder want to assign this Note, fill in the form below and have your
signature guaranteed:

I or we assign and transfer this Note to


--------------------------------------------------------------------------------

(Insert assignee's social security or tax ID number)
                                                    ----------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

(Print or type assignee's name, address and zip code) and irrevocably appoint

--------------------------------------------------------------------------------
agent to transfer this Note on the books of the Company. The agent may
substitute another to act for such agent.

Date:                  Your signature:
     ---------------                  ------------------------------------------
                                       (Sign exactly as your name appears on the
                                       other side of this Note)

                                       By:
                                          --------------------------------------
                                          NOTICE:  To be executed by an
                                          executive officer


Signature Guarantee:
                    ---------------------------


                                     A-2-7


<PAGE>   8


                       OPTION OF HOLDER TO ELECT PURCHASE


               If you wish to have this Note purchased by the Company pursuant
to Section 10.10 or 10.15 of this Indenture, check the appropriate box:

               Section 10.10 [ ]                Section 10.15 [ ]

               If you wish to have a portion of this Note purchased by the
Company pursuant to Section 10.10 or 10.15 of this Indenture, state the amount:

               $
                -------------

Date:                  Your signature:
     --------------                   ------------------------------------------
                                       (Sign exactly as your name appears on the
                                       other side of this Note)

                                       By:
                                          --------------------------------------
                                          NOTICE:  To be executed by an
                                          executive officer


Signature Guarantee:
                    ------------------------------


                                     A-2-8


<PAGE>   9


                                                                       EXHIBIT B

                    FORM OF LEGEND FOR BOOK-ENTRY SECURITIES


               Any Global Note authenticated and delivered hereunder shall bear
a legend (which would be in addition to any other legends required in the case
of a Restricted Note) in substantially the following form:

               THIS NOTE IS A GLOBAL NOTE WITHIN THE MEANING OF THIS INDENTURE
     HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITORY OR A
     NOMINEE OF A DEPOSITORY OR A SUCCESSOR DEPOSITORY. THIS NOTE IS NOT
     EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN
     THE DEPOSITORY OR ITS NOMINEE EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED
     IN THIS INDENTURE, AND NO TRANSFER OF THIS NOTE (OTHER THAN A TRANSFER OF
     THIS NOTE AS A WHOLE BY THE DEPOSITORY TO A NOMINEE OF THE DEPOSITORY OR BY
     A NOMINEE OF THE DEPOSITORY TO THE DEPOSITORY OR ANOTHER NOMINEE OF THE
     DEPOSITORY) MAY BE REGISTERED EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED
     IN THIS INDENTURE.

               UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED
     REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION
     ("DTC"), TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER,
     EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME
     OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
     REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH
     OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY
     TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY
     PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS
     AN INTEREST HEREIN.


                                       B-1


<PAGE>   10


                                                                       EXHIBIT C


                            Form of Certificate To Be
                          Delivered in Connection with
                    Transfers to Non-QIB Accredited Investors

Verio Inc.
8005 South Chester Street
Suite 200
Englewood, Colorado  80112

Ladies and Gentlemen:

               In connection with our proposed purchase of $      aggregate
principal amount of the 10-5/8% Senior Notes due 2009 (the "Notes") of Verio
Inc. (the "Company"), we confirm that:

               1. We understand that the Notes have not been registered under
     the Securities Act of 1933, as amended (the "Securities Act"), and, unless
     so registered, may not be sold except as permitted in the following
     sentence. We agree on our own behalf and on behalf of any investor account
     for which we are purchasing Notes to offer, sell or otherwise transfer such
     Notes prior to (x) the date which is two years (or such shorter period of
     time as permitted by Rule 144 under the Securities Act) after the later of
     the date of original issue of the Notes and (y) such later date, if any, as
     may be required by any subsequent change in applicable law (the "Resale
     Restriction Termination Date") only (a) to the Company, (b) pursuant to a
     registration statement which has been declared effective under the
     Securities Act, (c) so long as the Notes are eligible for resale pursuant
     to Rule 144A under the Securities Act, to a person we reasonably believe is
     a "qualified institutional buyer" under Rule 144A (a "QIB") that purchases
     for its own account or for the account of a QIB and to whom notice is given
     that the transfer is being made in reliance on Rule 144A, (d) pursuant to
     offers and sales that occur outside the United States to "foreign
     purchasers" (as defined below) in offshore transactions meeting the
     requirements of Rule 904 of Regulation S under the Securities Act, (e) to
     an institutional "accredited investor" within the meaning of subparagraph
     (a)(1), (2), (3) or (7) of Rule 501 under the Securities Act (an
     "Accredited Investor") that is purchasing for its own account or for the
     account of such an institutional "accredited investor," or (f) pursuant to
     any other available exemption from the registration requirements of the
     Securities Act, subject, in each of the foregoing cases, to any requirement
     of law that the disposition of our property or the property of such
     investor account or accounts be at all times within our or their control
     and to compliance


                                       C-1
<PAGE>   11


     with any applicable state securities laws. The foregoing restrictions on
     resale will not apply subsequent to the Resale Restriction Termination
     Date. If any resale or other transfer of the Notes is proposed to be made
     pursuant to clause (c) above prior to the Resale Restriction Termination
     Date, the transferor shall deliver a letter from the transferee
     substantially in the form of this letter to the Trustee, which shall
     provide, among other things, that the transferee is an Accredited Investor
     within the meaning of subparagraph (a)(1), (2), (3) or (7) of Rule 501
     under the Securities Act and that it is acquiring such Notes for investment
     purposes and not for distribution in violation of the Securities Act. Each
     purchaser acknowledges that the Company, the Trustee and the Transfer Agent
     and Registrar reserve the right prior to any offer, sale or other transfer
     prior to the Resale Restriction Termination Date of the Notes pursuant to
     clause (d), (e) or (f) above to require the delivery of an opinion of
     counsel, certification and/or other information satisfactory to the Company
     and the Trustee.

               2. We are an Accredited Investor or a QIB purchasing Notes for
     our own account or for the account of one or more Accredited Investors, and
     we are acquiring the Notes for investment purposes and not with a view to,
     or for offer or sale in connection with, any distribution in violation of
     the Securities Act or the securities laws of any state of the United States
     and we have such knowledge and experience in financial and business matters
     as to be capable of evaluating the merits and risks of our investment in
     the Notes, and we and any accounts for which we are acting are each able to
     bear the economic risk of our or its investment in the Notes for an
     indefinite period.

               3. We are acquiring the Notes purchased by us for our own account
     or for one or more accounts as to each of which we exercise sole investment
     discretion and we and any such account are (a) a QIB, aware that the sale
     is being made in reliance on Rule 144A under the Securities Act, (b) an
     Accredited Investor, or (c) a person other than a U.S. person ("foreign
     purchasers"), which term shall include dealers or other professional
     fiduciaries in the United States acting on a discretionary basis for
     foreign beneficial owners (other than an estate or trust) in offshore
     transactions meeting the requirements of Rules 903 and 904 of Regulation S
     under the Securities Act.

               4. We have received a copy of the Offering Memorandum and
     acknowledge that we have had access to such financial and other
     information, and have been afforded the opportunity to ask such questions
     of representatives of the Company and receive answers thereto, as we deem
     necessary in order to verify the information contained in the Offering
     Memorandum.

               5. We are not purchasing the Notes for or on behalf of, and will
     not transfer the Notes to, any pension or welfare plan (as defined in
     Section 3 of ERISA, except


                                       C-2
<PAGE>   12


     as may be permitted under ERISA and as described under "Notice to
     Investors" in the Offering Memorandum.

               6. In the event that we purchase any Notes, we will acquire Notes
     having an outstanding principal amount of at least $250,000 for our own
     account and $250,000 for each account for which we are acting.

               We understand that the Trustee and the Transfer Agent will not be
required to accept for registration of transfer any Notes acquired by us, except
upon presentation of evidence satisfactory to the Company and the Trustee that
the foregoing restrictions on transfer have been complied with. We further
understand that the Notes purchased by us will be in the form of definitive
physical certificates and that such certificates will bear a legend reflecting
the substance of this paragraph. We further agree to provide to any person
acquiring any of the Notes from us a notice advising such person that transfers
of such Notes are restricted as stated herein and that certificates representing
such Notes will bear a legend to that effect.

               We represent that you, the Company, the Trustee and others are
entitled to rely upon the truth and accuracy of our acknowledgments,
representations and agreements set forth herein, and we agree to notify you
promptly in writing if any of our acknowledgments, representations or agreements
herein cease to be accurate and complete. You are also irrevocably authorized to
produce this letter or a copy hereof to any interested party in any
administrative or legal proceeding or official inquiry with respect to the
matters covered hereby.

               We represent to you that we have full power to make the foregoing
acknowledgments, representations and agreements on our own behalf and on behalf
of any investor account for which we are acting as fiduciary agent.

               As used herein, the terms "offshore transaction," "United States"
and "U.S. person" have the respective meanings given to them in Regulation S
under the Securities Act.

               THIS LETTER SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE
WITH, THE LAWS OF THE STATE OF NEW YORK.

                                           Very truly yours,


                                           (Name of Purchaser)

By:
   --------------------------------

Date:
     ------------------------------


                                       C-3


<PAGE>   13


               Upon transfer, the Notes would be registered in the name of the
new beneficial owner as follows:



Name:
     ------------------------------

Address:
        ---------------------------


                                       C-4


<PAGE>   14


                                                                       EXHIBIT D


                       Form of Certificate To Be Delivered
                          in Connection with Transfers
                            Pursuant to Regulation S


                                                        -----------------, -----


U.S. Bank Trust National Association
180 East 5th Street
St. Paul, Minnesota  55101
Attention:  Corporate Trust Department


               Re: Verio Inc. (the "Company")
                   10-5/8% Senior Notes due 2009 (the "Securities")

Ladies and Gentlemen:

               In connection with our proposed sale of $      aggregate
principal amount of the Securities, we confirm that such sale has been effected
pursuant to and in accordance with Regulation S under the U.S. Securities Act of
1933, as amended (the "Securities Act"), and, accordingly, we represent that:

               (1) the offer of the Securities was not made to a person in the
     United States;

               (2) either (a) at the time the buy offer was originated, the
     transferee was outside the United States or we and any person acting on our
     behalf reasonably believed that the transferee was outside the United
     States, or (b) the transaction was executed in, on or through the
     facilities of a designated off-shore securities market and neither we nor
     any person acting on our behalf knows that the transaction has been
     pre-arranged with a buyer in the United States;

               (3) no directed selling efforts have been made in the United
     States in contravention of the requirements of Rule 903(b) or Rule 904(b)
     of Regulation S, as applicable;

               (4) the transaction is not part of a plan or scheme to evade the
     registration requirements of the Securities Act;


                                       D-1


<PAGE>   15


               (5) we have advised the transferee of the transfer restrictions
     applicable to the Securities;

               (6) if the circumstances set forth in Rule 904(c) under the
     Securities Act are applicable, we have complied with the additional
     conditions therein, including (if applicable) sending a confirmation or
     other notice stating that the Securities may be offered and sold during the
     restricted period specified in Rule 903(c)(2) or (3), as applicable, in
     accordance with the provisions of Regulation S; pursuant to registration of
     the Securities under the Securities Act; or pursuant to an available
     exemption from the registration requirements under the Securities Act; and

               (7) if the sale is made during a restricted period and the
     provisions of Rule 903(c)(3) are applicable thereto, we confirm that such
     sale has been made in accordance with such provisions.

               You and the Company are entitled to rely upon this letter and are
irrevocably authorized to produce this letter or a copy hereof to any interested
party in any administrative or legal proceedings or official inquiry with
respect to the matters covered hereby. Terms used in this certificate have the
meanings set forth in Regulation S.

                                   Very truly yours,

                                   [Name of Transferor]


                                   By:
                                      ------------------------------------------
                                        Authorized Signature


                                       D-2