Bug ID 496950: Flows may not be mirrored successfully when static routes and gateways are defined.

Last Modified: Oct 06, 2020

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
11.1.0, 11.2.0, 11.3.0, 11.4.0, 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, 11.5.3 HF2, 11.5.4, 11.5.4 HF1, 11.5.4 HF2, 11.5.4 HF3, 11.5.4 HF4, 11.5.5, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4

Fixed In:
12.0.0, 11.6.0 HF5, 11.5.6

Opened: Dec 16, 2014
Severity: 3-Major
Related AskF5 Article:


In certain circumstances, some L4 flows may not be successfully remirrored when a standby BIG-IP comes online. This involves a race condition when there are multiple routes and/or gateways defined; if the new standby device does not yet have the lasthop information when it gets the mirrored flow.


Not all flows will have been successfully remirrored to the standby device.


Using mirroring with layer 4 virtuals, with gateways and/or static routes defined.


Usually "bigstart restart tmm" will recover most or all of the L4 flows. This does not work perfectly all of the time, but is far less likely to encounter the error condition than a "bigstart restart" or "shutdown -r".

Fix Information

The standby device ignores the route to the client when accepting mirrored connections. If failover occurs without a route back to the client, the connection will still fail on failover.

Behavior Change