Bug ID 478439: Unnecessary re-transmission of packets on higher ICMP PMTU.

Last Modified: Sep 13, 2023

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

Known Affected Versions:
10.2.4, 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 HF1, 11.5.3 HF1, 11.2.1, 11.3.0, 11.4.0, 11.4.1, 11.6.0, 11.6.1, 11.6.2, 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, 12.1.0 HF1, 12.1.0 HF2, 12.1.1 HF1, 12.1.1 HF2, 12.1.2 HF1, 12.1.2 HF2

Fixed In:
12.0.0, 11.6.0 HF6, 11.5.3 HF2, 11.4.1 HF9, 11.2.1 HF15, 10.2.4 HF12

Opened: Sep 08, 2014

Severity: 3-Major

Related Article: K16651

Symptoms

LTM re-transmits TCP segments even when ICMP Path maximum transmission unit (PMTU) is higher than existing MTU.

Impact

Burst traffic generated.

Conditions

ICMP PMTU is higher than existing MTU.

Workaround

Disable Path MTU Discovery by entering the command: tmsh modify sys db tm.enforcepathmtu value disable.

Fix Information

Fixed unnecessary re-transmission of packets on higher ICMP Path maximum transmission unit (PMTU).

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips