Bug ID 456763: L4 forwarding and TSO can cause rare TMM outages

Last Modified: Apr 28, 2025

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

Known Affected Versions:
11.3.0, 11.4.1, 11.5.0, 11.5.1, 11.5.1 HF1, 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, 11.5.1 HF10, 11.5.1 HF11, 11.5.2, 11.5.2 HF1, 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, 11.5.3

Opened: Apr 10, 2014

Severity: 3-Major

Related Article: K16370

Symptoms

In certain rare circumstances using L4 forwarding and TSO, the MSS sizes on client and server sides in combination with internal processing can cause an internal mismatch resulting in a TMM crash.

Impact

This issue causes a failover or TMM outage.

Conditions

This applies only when using L4 forwarding virtuals with TSO; additional exact external conditions are still under investigation.

Workaround

This issue has no workaround at this time.

Fix Information

TMM will properly handle cases when the MSS sizes would have led to underflow.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips