Bug ID 1943257: HTTP monitor "last error" string sends incorrect response

Last Modified: Jun 28, 2025

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

Known Affected Versions:
16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3, 16.1.3.4, 16.1.3.5, 16.1.4, 16.1.4.1, 16.1.4.2, 16.1.4.3, 16.1.5, 16.1.5.1, 16.1.5.2, 16.1.6, 17.0.0, 17.0.0.1, 17.0.0.2, 17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3, 17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1, 17.1.2.2, 17.5.0, 17.5.1

Opened: May 16, 2025

Severity: 3-Major

Symptoms

When a recv string is used with an HTTP/HTTP2 monitor, the HTTP status code is collected and in the event of failure, the most recent value (from before the failure) is retrieved and used as part of the log output. This can result in a message that is misleading.

Impact

Generates a misleading log messages, difficulty in identifying the actual cause of the monitor failure. notice mcpd[8371]: 01070638:5: Pool /Common/http-pool member /Common/172.16.1.87:80 monitor status down. [ /Common/my-http-monitor: down; last error: /Common/my-http-monitor: Response Code: 200 (OK) @2025/05/12 07:30:25. ] [ was up for 0hr:0min:46sec ]

Conditions

- The BIG-IP system configured to monitor an HTTP/HTTP2 server.

Workaround

None

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips