Bug ID 1063453: FastL4 virtual servers translating between IPv4 and IPv6 may crash on fragmented packets.

Last Modified: Feb 07, 2024

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

Known Affected Versions:
15.1.2,, 15.1.3,, 15.1.4,, 15.1.5,, 15.1.6

Fixed In:
17.0.0,,, 14.1.5

Opened: Nov 22, 2021

Severity: 3-Major


Tmm crashes while passing IPv4-to-IPv6 traffic over FastL4.


All traffic is disrupted while the TMM restarts.


-- A FastL4 virtual server translates between IPv4 and IPv6. -- Fragment reassembly is not enabled in the FastL4 profile. -- A feature requiring asynchronous completion is configured including: asynchronous irules on LB events (LB_SELECTED, LB_FAILED, LB_PERSIST_DOWN, LB_QUEUED, SA_PICKED), persistence, sessiondb operations, HA, virtual rate limiting.


Configure the FastL4 profile to always reassemble fragments.

Fix Information


Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips