Bug ID 522310: ICMP errors cause the associated FastL4/TCP connection to be reset

Last Modified: Sep 13, 2023

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

Known Affected Versions:
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, 11.5.3 HF2, 11.5.4 HF1, 11.5.4 HF2, 11.5.4 HF3, 11.5.4 HF4, 11.5.0, 11.5.1, 11.5.2, 11.5.3, 11.5.4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10

Fixed In:
13.0.0, 11.6.1 HF2

Opened: May 08, 2015

Severity: 3-Major


When there are ICMP unreachable errors, the associated FastL4/TCP connection is reset by the BIG-IP.


FastL4/TCP connection from the client to BIG-IP will be reset.


There is an end to end connection from a client to server via BIG-IP and there is an ICMP error from the BIG-IP to pool member.



Fix Information

Provide a DB variable "TM.FastL4_rst_on_icmp" which is enabled by default. When enabled, the connection will be reset on ICMP errors. If the DB variable is disabled, ICMP errors will not result in the connection being torn down by the BIG-IP.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips