Symptoms

When using dynamic routing, it's possible that L4 connections fail to remirror after a restart on the standby device. Initial mirroring works as expected, but remirroring might not work.

Impact

Dynamically discovered routes might fail to remirror connections. One-way failover, similar to L7 virtual servers. Initial failover works as expected; subsequent failovers might drop connections.

Conditions

Using dynamic routes and mirroring, and either the active or standby restarts. If the active restarts, failover completes correctly, but connections might not remirror to the previously active device after it comes back online.

Workaround

Provide a static route instead of dynamic routes.

Fix Information

Remirroring L4 connections using dynamic routes works correctly. (Note that when using dynamic routes it is not guaranteed that the active and standby systems will use the same routes; if the same routing is required on both active and standby fails over, there might be some dropped connections.)

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips