Bug ID 601936: VPN client session hangup cause reported as unknown_error

Last Modified: Nov 07, 2022

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

Known Affected Versions:
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,,,,,,,, 12.1.4,, 12.1.5,,,, 12.1.6, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1

Fixed In:

Opened: Jun 28, 2016

Severity: 3-Major


When observing the APM logs for the reason a VPN client has initiated a session hangup (which then deletes the session), the session deletion cause is often reported as unknown_error, even though the error code looks like it should be decipherable: notice tmm[10740]: 01490567:5: /Common/AP_NA1:Common:18c98a2d: Session deleted (unknown_error, code - 24584).


The session deletion logs for VPN clients are misleading. APM expects and logs only the cause domain, and not the specific domain reason. In cases in which the client returns a code that contains both the domain and the reason, APM treats the cause as unknown instead of properly extracting the cause domain from the value.


-- VPN client initiates a session hangup (which subsequently deletes the session). -- Viewing the log file for the reason.


There is no true workaround. You can view the codes in the unknown_error logs, but it might take assistance from the F5 support organization to decode them.

Fix Information

APM now properly extracts the session termination cause from the code passed by the client when the client initiates a session hangup.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips