Bug ID 754143: TCP connection may hang after FIN

Last Modified: Apr 13, 2022

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
14.1.0.1, 14.1.0, 13.1.4

Fixed In:
15.0.0, 14.1.0.2, 13.1.4.1

Opened: Dec 27, 2018
Severity: 2-Critical
Related Article:
K45456231

Symptoms

TCP connections hang. Memory usage increases. TMM restarts. Numerous hanging connections reported similar to the following: -- config # tmsh show sys conn protocol tcp Sys::Connections 10.0.0.1:5854 10.0.0.250:80 any6.any any6.any tcp 449 (tmm: 0) none none 10.0.0.1:5847 10.0.0.250:80 any6.any any6.any tcp 449 (tmm: 0) none none 10.0.0.1:5890 10.0.0.250:80 any6.any any6.any tcp 449 (tmm: 0) none none 10.0.0.1:5855 10.0.0.250:80 any6.any any6.any tcp 449 (tmm: 0) none none 10.0.0.1:5891 10.0.0.250:80 any6.any any6.any tcp 449 (tmm: 0) none none

Impact

The BIG-IP system serverside connection eventually times out, and the clientside connection is orphaned. Those clientside connections hang indefinitely (even past the idle timeout). BIG-IP system memory increases, eventually leading to a possible TMM out-of-memory condition, requiring a TMM restart. Traffic disrupted while tmm restarts.

Conditions

Pool member fails to respond with an ACK to BIG-IP system serverside FIN (or sends a RST in response to the BIG-IP system's FIN).

Workaround

To delete the orphaned connections, you must restart the Traffic Management Microkernel (TMM) or restart the BIG-IP system. To restart the BIG-IP system, you can use either of the following procedures: Impact of either workaround: Service will be interrupted. If configured for high availability (HA), the BIG-IP system fails over to another device in the device group. Rebooting the BIG-IP system =========================== 1. Log in to the Advanced Shell (bash). 2. To restart the system, type the following command: reboot Restarting all blades on a VIPRION system ========================================= 1. Log in to bash. 2. To restart all the blades on the VIPRION system, type the following command: clsh shutdown -r now

Fix Information

TCP connections no longer hang under these conditions.

Behavior Change