Bug ID 1088597: TCP keepalive timer can be immediately re-scheduled in rare circumstances

Last Modified: Jul 24, 2024

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

Known Affected Versions:
13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 13.1.3.2, 13.1.3.3, 13.1.3.4, 13.1.3.5, 13.1.3.6, 13.1.4, 13.1.4.1, 13.1.5, 13.1.5.1, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 14.1.3.1, 14.1.4, 14.1.4.1, 14.1.4.2, 14.1.4.3, 14.1.4.4, 14.1.4.5, 14.1.4.6, 14.1.5, 14.1.5.1, 14.1.5.2, 14.1.5.3, 14.1.5.4, 14.1.5.6, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 15.1.6.1, 15.1.7, 15.1.8, 15.1.8.1, 15.1.8.2, 15.1.9, 15.1.9.1, 17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3

Fixed In:
17.1.1, 16.1.5, 15.1.10

Opened: Mar 21, 2022

Severity: 3-Major

Symptoms

In rare circumstances, the TCP timer is rescheduled immediately due to the utilization of the interval encompassing also the idle_timeout.

Impact

High CPU utilization potentially leading to reduced performance.

Conditions

Virtual Server with: - TCP Profile - SSL Profile with alert timeout configured Another way this can occur is by manually deleting connections, which effectively only sets the idle timeout to 0.

Workaround

If the alert timeout is not re-enabled in the SSL Profile that should be sufficient.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips