Last Modified: Aug 19, 2026
Affected Product(s):
BIG-IP TMOS
Known Affected Versions:
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, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 11.6.0, 11.6.0 hf1, 11.6.0 hf2, 11.6.0 hf3, 11.6.0 hf4, 11.6.0 hf5, 11.6.0 hf6, 11.6.0 hf7, 11.6.0 hf8, 11.6.1, 11.6.1 hf1, 11.6.1 hf2, 11.6.2, 11.6.2 hf1, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 12.0.0, 12.0.0 hf1, 12.0.0 hf2, 12.0.0 hf3, 12.0.0 hf4, 12.1.0, 12.1.0 hf1, 12.1.0 hf2, 12.1.1, 12.1.1 hf1, 12.1.1 hf2, 12.1.2, 12.1.2 hf1, 12.1.2 hf2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4, 12.1.4.1, 12.1.5, 12.1.5.1, 12.1.5.2, 12.1.5.3, 12.1.6
Fixed In:
13.0.0, 11.6.4
Opened: Dec 14, 2016 Severity: 3-Major Related Article:
K20160253
When a preferred device becomes available and takes over due to an Auto-Failback configuration, the takeover is not performed as a smooth handoff, but instead results in both devices becoming Active for the network failover timeout period (3 seconds).
Since both nodes are Active for (by default) 3 seconds, this may cause network traffic to be dropped or interrupted during the overlap interval. In addition, the Active/Active overlap may not resolve in favor of the preferred device. When this happens, the preferred device attempts to Auto-Failback again after the Auto-Failback expires, and the process repeats forever.
This problem affects traffic groups on VIPRION systems configured with HA Order and Auto-Failback enabled.
Do not configure Auto-Failback on VIPRION.
The devices perform a clean handoff during Auto-Failback, with no Active/Active overlap.