Bug ID 812693: Connection in FIN_WAIT_2 state may fail to be removed

Last Modified: Apr 17, 2024

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

Known Affected Versions:
13.1.1,,,,, 13.1.3,,,,,,, 13.1.4,, 13.1.5,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,,,,,, 14.1.3,, 14.1.4,,,,,,, 14.1.5,,,,,, 15.0.0, 15.0.1,,,,, 15.1.5,, 15.1.6,, 15.1.7, 15.1.8,,, 15.1.9,, 15.1.10,,,

Opened: Aug 06, 2019

Severity: 3-Major


If a connection that has a fully closed client-side, but a server-side still in FIN_WAIT_2, receives a SYN matching the same connflow, the idle time is reset. This can result in the fin-wait-2-timeout never being reached. The SYN will be responded to with a RST - 'TCP Closed'


Connection may fail to be removed in a timely manner. New connection attempts are RST with 'TCP Closed'


- Client side connection has been fully closed. This may occur if a client SSL profile is in use and an 'Encrypted Alert' has been received. - Server side has sent a FIN which has been ACK'd, but no FIN has been received from the server. - SYN received matching the existing connflow before the FIN-WAIT-2-timeout has been reached (300 default).


You can use either of the following: -- Ensure servers are sending FIN's so as not to leave the connection in a FIN_WAIT_2 state. -- Mitigate the issue by lowering the FIN-WAIT-2-timeout to a smaller value, e.g., FIN-WAIT-2-timeout 10.

Fix Information


Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips