Exhibit 2.1
 AGREEMENT AND PLAN OF MERGER
 THIS AGREEMENT AND PLAN OF MERGER Agreement Parent Merger Sub Company Significant
Shareholder Significant Shareholders Party Parties Appendix A
 WHEREAS Merger
 WHEREAS
 WHEREAS Offer Letter Employee Agreements Exhibit A 280G Waiver
 WHEREAS Appendix B Key Shareholders Exhibit B Shareholders Agreement
 WHEREAS
 WHEREAS




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NOW, THEREFORE
 ARTICLE I
THE MERGER
 The Merger Surviving Corporation
 Effective Time Exhibit C Plan of Merger Effective Time
 Effect of the Merger
 Articles of Incorporation; Bylaws Exhibit D Exhibit E
 Directors and Officers
 - 2 -




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Effect of Merger on Capital Stock
 Merger Consideration
   plus plus plus
   - 3 -




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Performance Payments Performance Payment Recipient
 Beta Version Beta Release
 General Availability (GA) Version GA Release
 - 4 -




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Effect of Force Majeure
 Conduct During Performance Payment Period
 Stock Options
 Option Termination Agreement plus plus plus
  Warrants
 Series A Warrant Termination Agreement
 - 5 -




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Common Warrant Termination Agreement plus plus plus
 Deferred Payment Deferred Payment
 Adjustments to Merger Consideration
  - 6 -




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Estimated Closing Adjustment
 Holder
 Post-Closing Adjustment
     - 7 -




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Post-Closing Adjustment
 Surrender of Certificates
 Exchange Procedures Certificates Exhibit F Letter of Transmittal
 No Liability
 - 8 -




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Withholding of Tax
 Lost, Stolen or Destroyed Certificates
 No Further Ownership Rights in Company Stock
 Dissenting Shares Dissenting Shares
 Further Action
 - 9 -




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ARTICLE II
CLOSING
 Time and Place of the Closing
 Deliveries
 Shareholders Representative
 Shareholders Representative
  - 10 -




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ARTICLE III
REPRESENTATIONS AND WARRANTIES RELATING TO
THE COMPANY
  Organization, Corporate Power and Records
 Schedule 3.1(a) Schedule 3.1(a)
 - 11 -




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Authority for Agreement
 No Violation to Result Schedule 3.3
 - 12 -




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Schedule 3.3
 Capitalization
 Schedule 3.4(a) Schedule 3.4(b) Schedule 3.4(a)
 Schedule 3.4(b) Schedule 3.4(b) Schedule 3.4(b)
 Schedule 3.4(c)
 - 13 -




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Financial Statements
 Schedule 3.5(a) Schedule 3.5(a) Schedule 3.5(a)
 Schedule 3.5(b) Schedule 3.5(b) Schedule 3.5(b)
 - 14 -




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Liabilities Schedule 3.6 Schedule 3.6
 Adverse Changes Schedule 3.7
 Employee Benefit Plans
 Schedule 3.8(a)(i) Company
Plan Schedule 3.8(a)(ii)
 - 15 -




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- 16 -




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- 17 -




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Employee Matters
 Schedule 3.9(a)(i) Company Employees Schedule 3.9(a)(ii) Schedule 3.9(a)(iii)
  - 18 -




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Schedule 3.9(c)(i) Schedule
3.9(c)(ii)
  Schedule 3.9(e)
 Taxes
 Schedule 3.10(a)
 - 19 -




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Schedule 3.10(b)
 Schedule 3.10(c)
 Schedule 3.10(d) Schedule 3.10(e)
 Schedule 3.10(e)
 Schedule 3.10(f)
 - 20 -




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Schedule 3.10(i) Potential Parachute Recipient
  Schedule 3.10(k)
 - 21 -




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Schedule 3.10(n)
         - 22 -




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Property
 Schedule
3.11(a) Facilities Schedule 3.11(a) Schedule 3.11(a) Schedule 3.11(a) Schedule 3.11(a)
 Schedule 3.11(b) Schedule 3.11(b) Schedule 3.11(b) Schedule 3.11(b) Schedule 3.11(b)
  - 23 -




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Contracts
 Schedule 3.12(a)(1) Schedule 3.12(a)(2) Schedule 3.12(a)(2)
 Schedule 3.12(b) Schedule
3.12(a)(1) Schedule 3.12(a)(1) Schedule 3.12(b)
 Claims and Litigation Schedule 3.13 Schedule 3.13 Schedule
3.13
 - 24 -




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Compliance with Laws
 Schedule 3.14
   - 25 -




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Environmental and Safety Matters
 Insurance Schedule 3.16 Schedule 3.16
 Intellectual Property
  Schedule 3.17(b)
 - 26 -




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Schedule 3.17(b) Schedule 3.17(b) Schedule 3.17(b)
 Schedule 3.17(c) Schedule
3.17(c)
 - 27 -




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End-User Agreements Services Agreements Product
Agreements Schedule 3.17(d) Schedule 3.17(d) Schedule 3.17(d) Schedule 3.17(d) Schedule 3.17(d)
 Schedule 3.17(e)(i)
 - 28 -




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Schedule
3.17(e)(ii) Schedule 3.17(e)(ii)
 Schedule 3.17(f)
 Schedule 3.17(g) Schedule
3.17(g) Schedule 3.17(g)
   - 29 -




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Schedule 3.17(j) Domain Names Schedule 3.17(j) Content
 Schedule 3.17(k)
  Schedule 3.17(m) Company Open Source Projects Schedule 3.17(m) Schedule
3.17(m) Schedule 3.17(m)
 - 30 -




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Use of User Data
 Privacy Policies
     Schedule 3.17(o)
 Schedule 3.17(p)
 - 31 -




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Related Party Transactions Schedule 3.18
 Customers Schedule 3.19 Significant Customers
 Brokers
 Bank Accounts; Powers of Attorney Schedule 3.21
 Disclosure
 - 32 -




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ARTICLE IV
REPRESENTATIONS AND WARRANTIES OF THE SIGNIFICANT SHAREHOLDERS
  Authority for Agreement
 No Violation to Result Schedule 4.2 Schedule 4.2 Schedule 4.2
 Litigation
 Brokers Schedule 3.20
 Disclosure
 - 33 -




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ARTICLE V
REPRESENTATIONS AND WARRANTIES OF PARENT AND MERGER SUB
  Organization
 Authority for Agreement
 No Violation to Result
 - 34 -




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Interim Operations of Merger Sub
 Brokers
 Disclosure
 ARTICLE VI
ADDITIONAL AGREEMENTS
 Access to Properties and Records
 Interim Covenants of the Company Schedule 6.2
 - 35 -




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Schedule 3.12
    - 36 -




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Publicity and Disclosure; Confidentiality
   - 37 -




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No Solicitation Non-Exclusive Licenses Competing Transaction
 Notification of Certain Matters
 Tax Matters
 Preparation of Tax Returns after Closing
  - 38 -




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Parent Prepared Return
   Allocation of Taxes
 Tax Proceedings
 Cooperation, Access to Information, and Record Retention
 - 39 -




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Tax Certificates
 Termination of Tax Sharing Agreements
 Transfer Taxes
 Litigation Support
 Reasonable Efforts
 Company Employees
 - 40 -




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Takeover Statutes
 Employee Benefits Matters
 Company Shareholder Approval
 Recommendation Consent Solicitation Statement
 Written Consents
 - 41 -




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Nonconsenting Shareholders Information Statement
  280G
Shareholder Approval
 ARTICLE VII
CONDITIONS TO THE OBLIGATIONS OF PARENT AND MERGER SUB
  - 42 -




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Representations and Warranties
 Performance
 No Litigation
 No Material Adverse Effect
 Governmental, Regulatory and Other Consents and Approvals Schedule 3.3
 Shareholders Agreement
 Indebtedness.
 Warrants
 Company Employees
 - 43 -




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Written Consents
 Closing Deliveries of the Company
      Exhibit G
   - 44 -




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ARTICLE VIII
CONDITIONS TO THE COMPANYS OBLIGATIONS
  Representations and Warranties True at the Closing Date
 Performance
 No Litigation
 Closing Deliveries of Parent and Merger Sub
   - 45 -




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ARTICLE IX
INDEMNITY
 General Indemnification Appendix C
 Claims for Indemnification.
 Indemnifying Party Claim Notice
 - 46 -




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Objection Notice provided further Objection Deadline
  Third Party Claims provided, however, provided, however provided, however,
 - 47 -




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Survival of Representations, Warranties and Covenants provided, that Fraud Claims Excluded
Claims
 Limitations on Indemnification
 Threshold Amount provided that provided that
 General Cap provided that
  No Contribution
 - 48 -




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Releasees
 Right of Offset
 Exclusive Remedy
 No Double Recovery; Use of Insurance
 - 49 -




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ARTICLE X
COVENANT NOT TO COMPETE
 Prohibited Activities rd
      Damages
 - 50 -




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Reasonable Restraint
 Independent Covenant
 ARTICLE XI
TERMINATION
 Termination
    - 51 -




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provided that
     ARTICLE XII
MISCELLANEOUS
 Successors and Assigns provided however
 - 52 -




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Governing Law
 Consent to Jurisdiction
 Waiver of Jury Trial
 Specific Performance
 Severability
 - 53 -




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Amendment
 Waiver
 Notices
  :
  
 - 54 -




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Expenses
 - 55 -




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Complete Agreement
 Absence of Third Party Beneficiary Rights
 Mutual Drafting
 Further Representations
 Gender vice versa
 Headings
 Counterparts
  - 56 -




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IN WITNESS WHEREOF
 SOURCEFIRE, INC.By:
    /s/ Todd P. HeadleyName:
    Todd P. HeadleyTitle:
    Chief Financial Officer CLOUD ACQUISITION CORPORATIONBy:
    /s/ Todd P. HeadleyName:
    Todd P. HeadleyTitle:
    President IMMUNET CORPORATIONBy:
    /s/ Oliver FriedrichsName:
    Oliver FriedrichsTitle:
    Chief Financial OfficerSIGNIFICANT SHAREHOLDERS/s/ Oliver FriedrichsOliver Friedrichs/s/ Alfred HugerAlfred HugerSHAREHOLDERS REPRESENTATIVE/s/ Oliver FriedrichsOliver Friedrichs Signature Page to Agreement and Plan of Merger




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APPENDICES
    EXHIBITS




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APPENDIX A
 DEFINED TERMS
 280G Shareholder Approval
 280G Waiver
 Accounting Firm
 Acquired Business
 Affiliate
 Aggregate Preference Amount
 Agreement
 Articles of Incorporation
 Balance Sheet
 Balance Sheet Date
 Beta Release
 Beta Version Exhibit H-1
 Certificates
 CGCL




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Claim Notice
 Closing
 Closing Adjustments
 Closing Amount
 Closing Balance Sheet
 Closing Date
 Closing Net Working Capital
 Code
 Common Per Share Closing Amount
 Common Warrant
 Common Warrant Termination Agreement
 Company
 Company Common Stock
 Company Employees
 Company Intellectual Property Rights




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Company Open Source Projects
 Company Option Plan
 Company Options
 Company Plan
 Company Stock
 Competing Transaction
 Consent Solicitation Statement
 Content
 Contract
 Corporate Transaction
 Damages
 Deferred Payment
 Dissenting Shares
 Domain Names
 Effective Time
 Employee Agreements




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Employee Incentive Plan
 Encumbrance
 End-User Agreements
 Enterprise Software Product Exhibits H-1 and H-2
 Environment
 Environmental Laws
 ERISA
 ERISA Affiliate
 Estimated Closing Adjustment
 Estimated Closing Balance Sheet
 Estimated Net Working Capital




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Estimated Net Working Capital Deficit
 Estimated Net Working Capital Surplus
 Excluded Claims
 Facilities
 Financial Statements
 FIRPTA
 FIRPTA Notification Letter
 First Performance Payment
 First Pro Rata Performance Amoun
 Fraud Claims
 Fully Diluted Share Number
 GAAP




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GA Release
 GA Version Exhibit H-2
 General Cap
 Government
 Government Authority
 Government Bid
 Government Contract
 Hazardous Substance
 Holder
 Indebtedness




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Indemnified Party
 Information Statement
 Intellectual Property Rights
 Interim Financials
 IRS
 Key Shareholders
 Knowledge
 Laws
 Letter of Intent
 Letter of Transmittal
 Liability Liabilities




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Material Adverse Effect provided that
 Merger
 Merger Consideration
 Merger Sub
 Merger Sub Common Stock
 Nonconsenting Shareholders
 Non-Exclusive Licenses
 Non-Ordinary Course Liabilities
 Objection Deadline
 Objection Notice
 Offer Letter
 Option Proceeds
 Option Termination Agreement




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Parent
 Parent Confidential Information
 Parent Prepared Return
 Party Parties
 Performance Payments
 Performance Payment Recipient
 Person
 Plan of Merger
 Post-Closing Adjustment
 Potential Parachute Recipient
 Privacy Policies
 Proceeding
 Product
 Product Agreements
 Proprietary Information Agreement
 Pro Rata Share
 Public Software




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Recommendation
 Related Party
 Release
 Releasees
 Representatives
 Requisite Vote
 Second Performance Payment
 Second Pro Rata Performance Amoun
 Series A Per Share Closing Amount
 Series A Per Share Preference
 Series A Preferred Stock
 Series A Warrant




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Series A Warrant Termination Agreement
 Services
 Services Agreements
 Shareholders
 Shareholders Agreement
 Shareholders Representative
 Significant Contract
 Significant Customers




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Significant Shareholder
 Statement of Closing Liabilities
 Statement of Estimated Closing Liabilities
 Subsidiary
 Surviving Corporation
 Takeover Statute
 Target Net Working Capital
 Tax
 Tax Return
 Taxing Authority
 Third Party Intellectual Property Rights Schedule 3.17(b)
 Threshold Amount
 Trademarks




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Transaction Expenses
 Transfer Taxes
 User Data
 Warrant Proceeds
 Welfare Plan
 Written Consents
 Year-End Financials