Bug ID 641753: Syncookies activated on a genuine connection gets reset almost 30-50% of the time

Last Modified: Apr 28, 2025

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

Known Affected Versions:
11.6.1, 11.6.1 HF1, 11.6.1 HF2, 11.6.2, 11.6.2 HF1, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 11.6.5, 11.6.5.1, 11.6.5.2, 11.6.5.3, 12.0.0, 12.0.0 HF1, 12.0.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 12.1.2 HF1, 12.1.2 HF2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4, 12.1.4.1, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1

Fixed In:
13.1.0, 12.1.5

Opened: Jan 26, 2017

Severity: 3-Major

Symptoms

Syncookies activated on a genuine connection to a TCP-based virtual server gets reset almost 30%-50% of the time.

Impact

Potential performance impact.

Conditions

-- VADC platform when syncookie protection mode is configured and activated on a virtual server. Note: This issue might also occur on v12.x systems using the L7-intelligent-fpga HSB firmware.

Workaround

None.

Fix Information

When syncookie protection mode is activated, all the genuine connections go through as expected, so there are no resets.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips