Bug ID 1983553: Unable to load config after upgrading to v17.5.x with the Syntax Error: "tcp-ack-flood" unknown property

Last Modified: Jul 30, 2025

Affected Product(s):
BIG-IP AFM, Install/Upgrade(all modules)

Known Affected Versions:
17.5.0, 17.5.1

Opened: Jul 16, 2025

Severity: 2-Critical

Symptoms

After upgrading a BIG-IP AFM device from version 16.1.5.1 to 17.5.0, the device fails to come online. Syntax Error:(/config/bigip.conf at line: 2737) "tcp-ack-flood" unknown property

Impact

The device fails to come online. This means the system is not operational which is in offline state.

Conditions

Network vectors can be Mitigate state. Once dynamic signature detection is enabled, the load fails after upgrade to v17.5.0.

Workaround

-- Manually remove the duplicate state entry in bigip.conf. -- Perform "tmsh load sys config verify" or reboot

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips