Last Modified: Oct 06, 2020
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Known Affected Versions:
11.2.0, 11.2.1, 11.3.0, 11.4.0, 11.4.1, 11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.10, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5
12.0.0, 11.6.0 HF6, 11.5.3 HF2
Opened: May 05, 2015
Related AskF5 Article: K08025400
After failover of an L4 flow that is using keep-alive, the keep-alive transmissions do not resume after traffic has flowed through the BIG-IP system.
Flows after failover with TCP keep-alive age out and expire even if traffic is available to set the sequence numbers. Depending on the configuration options, subsequent packets may reset or transparently create a new flow (if TCP loose initiation is enabled).
Using HA mirroring of L4 connections, with keep-alive enabled on the profile for TCP. After a failover, there was traffic before the flow timed out, then the traffic becomes idle. If there is no traffic after failover, the correct sequence numbers are unknown, then this is expected behavior: the flow times out due to inactivity. If there is traffic after failover, the correct TCP sequence numbers are known; if there is traffic after failover, and then the flow becomes idle, keep-alive transmissions should resume.
Keep-alive transmissions now resume after failover of flows on an L4 virtual, when the sequence number is known