Bug ID 2208413: APM NLAD encounters a "Too many open files" error

Last Modified: Sep 02, 2026

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

Fixed In:
21.1.0.2, 17.5.1.9, 17.1.3.5

Opened: Jan 19, 2026

Severity: 3-Major

Symptoms

Following message is seen in /var/log/apm . Dec 11 04:42:01 <example.com> err nlad[xxxx]: xxxxxxx:3: <0xxxxxx> client[109]: DC[x.x.x.x]: schannel[x]: STL exception: eventfd_select_interrupter: Too many open files

Impact

When NLAD exhausts its file descriptors, NTLM user authentication fails.

Conditions

Occurs when there are frequent changes to the NTLM configuration while active user sessions are using the current configuration.

Workaround

Restarting TMM with bigstart should resolve the issue.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips