Symptoms

The measured number of pending requests is two times higher than actual.

Impact

Server stress mechanism is more sensitive than planned. A temporary traffic spike can cause unnecessary DoS mitigation start. Note: The admd process provides stress-based DoS detection and mitigation control. When admd is not running, there is no stress-based anomaly detection or behavioral statistics aggregation.

Conditions

Virtual server configured with a Behavioral DoS profile.

Workaround

Modify the adm.health.sensitivity value. For example, to change health sensitivity from 50 to 500, run the following command: tmsh modify sys db adm.health.sensitivity value 500

Fix Information

Fixed initial adm flow sampling, so that the measured number of pending requests now equals actual.

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips