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Cisco Bug: CSCut63933 - ZBFW: TCP Sequence Numbers Improperly Modified w/ CWS + ZBFW

Last Modified

Mar 05, 2018

Products (1)

  • Cisco IOS

Known Affected Releases

15.4(3)

Description (partial)

Symptom:
In some cases, ZBFW may incorrectly modify the sequence numbers of FIN ACK packets traversing from the server back to the client with CWS enabled.  This may cause some webpages to hang and not display properly and ultimately be reset by ZBFW.

Conditions:
1.  ZBFW must be enabled on the ISR
2.  ISR must be redirecting traffic to Cisco Cloud Web Security
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Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
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