Bug ID 1094145: AFM does not detect NXDOMAIN attack when DNS cache is activated.

Last Modified: Sep 13, 2023

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

Known Affected Versions:
15.1.4,, 15.1.5,, 15.1.6,, 15.1.7, 15.1.8,,, 15.1.9,

Fixed In:

Opened: Apr 05, 2022

Severity: 4-Minor


When the DNS cache is activated, the NXDOMAIN DoS vector does not increase for the virtual server context. As a result, NXDOMAIN flood attack is never detected/mitigated at the virtual server context. At the device level, NXDOMAIN stats are incorrect.


NXDOMAIN flood attack is not detected/mitigated at the virtual server context.


-- DNS cache is activated -- An NXDOMAIN DoS vector occurs



Fix Information

An NXDOMAIN flood attack can be detected and mitigated when DNS cache is enabled.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips