Preview Tool

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

Last Modified

Mar 05, 2018

Products (1)

  • Cisco IOS

Known Affected Releases


Description (partial)

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.

1.  ZBFW must be enabled on the ISR
2.  ISR must be redirecting traffic to Cisco Cloud Web Security
Bug details contain sensitive information and therefore require a account to be viewed.

Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
  • Number of Related Support Cases
Bug information is viewable for customers and partners who have a service contract. Registered users can view up to 200 bugs per month without a service contract.