Last Modified: Jan 20, 2023
Affected Product:
See more info
BIG-IP LTM
Known Affected Versions:
16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3
Opened: Mar 19, 2020
Severity: 3-Major
SYNs received with TSVal <= TS.Recent are dropped without sending an ACK in FIN-WAIT-2 state.
The new TCP connection cannot infer the half-open state of Local TCP connections, which prevents faster recovery of half-open connections. The local TCP connection stays around for a longer time.
-- Timestamps are enabled in TCP profile. -- Local TCP connection is in FIN-WAIT-2 state. -- Remote TCP connection abandoned the flow. -- A new TCP connection sends a SYN with TSVal <= TS.Recent to the local connection.
There are two workarounds: -- Reduce the Fin Wait 2 timeout (the default: 300 sec) so that TCP connection is terminated sooner. -- Disable TCP Timestamps.
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