Support Center > Search Results > SecureKnowledge Details
'TCP out of Sequence' logs in SmartView Tracker Technical Level
Symptoms
  • "TCP out Of Sequence" logs in SmartView Tracker.
  • In traffic capture, the packets that create the logs are "TCP Keep-Alive".
Cause

A "TCP Keep-Alive" packet is sent with a sequence number which is one less than the sequence number the receiver is expecting, because the receiver has already ACKed the sequence number of the Keep-Alive. This causes the Security Gateway to detect the packets as "TCP out of Sequence".

Example of "TCP Keep-Alive" packet in WireShark:


Solution
Note: To view this solution you need to Sign In .