Bug ID 565799: CPU Usage increases when using masquerade addresses

Last Modified: Aug 19, 2026

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

Known Affected Versions:
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, 11.6.4, 11.6.5, 11.6.5.1, 11.6.5.2, 11.6.5.3, 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

Fixed In:
13.0.0, 12.1.2

Opened: Jan 05, 2016

Severity: 3-Major

Symptoms

When using masquerade addresses, CPU usage increases. This can ultimately lead to a reduction in device capacity.

Impact

Possible performance degradation or reduction in capacity

Conditions

This can occur if one or more of your traffic groups is configured to use a MAC Masquerade address.

Workaround

None

Fix Information

Performance of masquerade address checks is restored.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips