Bug ID 478257: Unnecessary re-transmission of packets on ICMP notifications even when MTU is not changed

Last Modified: Sep 13, 2023

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

Known Affected Versions:
10.2.0, 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, 11.5.4 HF3, 11.5.3 HF2, 11.4.1 HF9, 11.2.1 HF15, 10.2.4 HF12

Opened: Sep 06, 2014

Severity: 3-Major

Related Article: K16449

Symptoms

Re-transmission of fragment needed packets.

Impact

Burst traffic generated.

Conditions

Multiple ICMP Destination Unreachable with Fragmentation needed code messages.

Workaround

Disable Path MTU Discovery by doing the following, "tmsh modify sys db tm.enforcepathmtu value disable"

Fix Information

BIG-IP no longer re-transmits packets if the MTU is not changed.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips