Bug ID 757442: A missed SYN cookie check causes crash at the standby TMM in HA mirroring system

Last Modified: Jul 12, 2023

Affected Product(s):
BIG-IP All(all modules)

Known Affected Versions:
13.1.0,,,,,,,,, 13.1.1,,,,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,,,,,, 14.1.3,

Fixed In:
15.0.0, 14.1.4, 13.1.3

Opened: Feb 02, 2019

Severity: 3-Major


In a high availability (HA) mirroring configuration, an L7 packet SYN cookie check may be skipped on the standby unit and eventually causes TMM to crash.


TMM crashes on the standby device. No connections shown on the standby unit even when mirroring isenabled.


-- L7 traffic being passed to an HA configuration that is configured for mirroring traffic. -- Failover occurs.


Do not use HA mirroring.

Fix Information

The system now provides SYN cookie checks for L7 mirrored packets on the standby system.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips