Exhibit 31.2

CERTIFICATIONS

I, Timothy D. Heffner, certify
  that:

| | 1. | I have reviewed
      this quarterly report on form 10-Q of Foundry Networks, Inc.;                                                                                                                                                                                                                                               
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| | 2. | Based on my
      knowledge, this report does not contain any untrue statement of a material
      fact or omit to state a material fact necessary to make the statements made,
      in light of the circumstances under which such statements were made, not
      misleading with respect to the period covered by this report;
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| | 3. | Based on my
      knowledge, the financial statements, and other financial information included
      in this report, fairly present in all material respects the financial condition,
      results of operations and cash flows of the registrant as of, and for, the
      periods presented in this report;                   
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| | 4. | The registrants
      other certifying officer(s) and I are responsible for establishing and maintaining
      disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e)
      and 15d-15(e)) for the registrant and have:                                                                                  
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| |    | (b)                                                                                                                                                                                                                                                                                                                               
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| |    | (d)                                                                                                                                                                                                                                                                                                                               
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| | 5. | The registrants
      other certifying officers and I have disclosed, based on our most recent
      evaluation of internal control over financial reporting, to the registrants
      auditors and the audit committee of the registrants board of directors
      (or persons performing the equivalent function):           
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| |    | (a)                                                                                                                                                                                                                                                                                                                               
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| |    | (b)                                                                                                                                                                                                                                                                                                                               

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