Last Modified: Sep 13, 2023
Affected Product(s):
BIG-IP LTM
Known Affected Versions:
11.5.1, 11.5.2, 11.5.3, 11.5.4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 11.6.1, 11.6.2, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 11.6.5, 11.6.5.1, 11.6.5.2, 11.6.5.3
Opened: Jun 30, 2016 Severity: 3-Major
You notice that L7 connections on the standby unit are increasing and may not be cleared until the tcp timeout.
Connections increase unnecessarily on the standby unit.
This can occur when using mirroring when syn cookies are enabled. It is more severe with hardware syn cookies but still occurs with software syn cookies.
Although it does not completely clear the condition, you can disable hardware syncookies to work around this problem. In tmsh: modify /ltm profile tcp <profile_name> hardware-syn-cookie disable
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