Guest

Preview Tool

Cisco Bug: CSCtc69845 - Unexpected ACK is sent from ASA during multiple retransmission

Last Modified

Nov 08, 2016

Products (1)

  • Cisco ASA 5500-X Series Firewalls

Known Affected Releases

8.0(4)

Description (partial)

Symptom:

In case of Smart Tunnel WebVPN, ASA is an end point of WebVPN tunnel
and the initiator of TCP connection with the target server.

On the side of non-WebVPN TCP connection,
and when ASA can't receive any acknowledge packets from server,
ASA repeatedly sends not only retransmitting packet
but unexpected ACK which has strange sequence/acknowledge number,
which is minus 1 of the one of retransmitting packet.

This unexpected ACK is sent from ASA every minute
until the connection is closed.

Conditions:

This problem is found while ASA retransmits decrypted GET packets from Smart Tunnel client.
Bug details contain sensitive information and therefore require a Cisco.com 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.