Bug ID 494084: Certain rapidly-terminating UDP virtuals may core on standby

Last Modified: Oct 16, 2023

Affected Product(s):
BIG-IP None(all modules)

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, 11.6.0, 11.6.1, 11.6.2, 11.6.3,,,,, 11.6.4, 11.6.5,,,, 12.1.0 HF1, 12.1.0 HF2, 12.1.1 HF1, 12.1.1 HF2, 12.1.2 HF1, 12.1.2 HF2

Fixed In:

Opened: Dec 03, 2014

Severity: 3-Major


Based on an internal race condition, it is possible for certain flows to cause cores on standby BIG-IPs when using connection mirroring on layer 7 VIPs. This does not apply to use of mirroring on Performance or Performance (HTTP) virtuals.


Restart of the standby tmm. No connections are affected, though if packets are set to require acknowledgements from the standby there may be a brief delay in processing for some or all connections.


Standard UDP virtual using connection mirroring.



Fix Information

The internal race condition is removed.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips