Bug ID 726900: Switching from FastL4 or TCP profiles to an ipother profile may leave a virtual server with stale TCP syncookie parameters

Last Modified: Sep 14, 2023

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

Known Affected Versions:
13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 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, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.0.1.1, 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, 15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2, 15.0.1.3, 15.0.1.4

Opened: Jul 05, 2018

Severity: 2-Critical

Symptoms

Virtual server may attempt to use syncookies on first SYN packet rather than allowing the connection to pass through to the real server.

Impact

The configured 'ip-other' virtual server will fail to accept all traffic. For example, a TCP or a UDP flow which should have been accepted and processed by the 'ip-other' virtual server will be dropped incorrectly, trying to enforce 'Syn Cookie' validation.

Conditions

Modifying a virtual server (CLI/iControl/GUI) to switch from FastL4 or TCP profiles to an 'ip-other' profile.

Workaround

When switching a virtual server profile from FastL4/TCP to the 'ip-other' profile, delete the virtual server and then re-add it with the 'ip-other' profile.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips