Bug ID 947937: HTTP iRule commands may fail to execute within the "fallback-host" HTTP profile field.

Last Modified: Sep 14, 2022

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
14.1.0,,,,,, 14.1.2,,,,,,,,, 14.1.3,, 14.1.4,,,,,,, 14.1.5,, 15.0.0, 15.0.1,,,,, 15.1.0,,,,,, 15.1.1, 15.1.2,, 15.1.3,, 15.1.4,, 15.1.5,, 15.1.6,, 16.0.0,, 16.0.1,,

Fixed In:

Opened: Sep 23, 2020
Severity: 4-Minor


The BIG-IP system can redirect a request to a fallback host when the target pool is unavailable. If the configured fallback host within the HTTP profile contains HTTP iRule commands such as HTTP::host or HTTP::uri, the corresponding HTTP request can fail. A connection reset may be encountered instead.


When utilizing the HTTP profile with "fallback-host" profile option with HTTP iRule commands, incorrect connection resets can be seen by the client instead of the correct HTTP response.


- HTTP profile with "fallback-host" profile option configured containing an HTTP iRule command.


Attaching an iRule containing HTTP::redirect or similar command to the virtual server can be used instead of the fallback host-profile option to redirect traffic to another virtual server.

Fix Information

The HTTP "fallback-host" profile option with HTTP iRule commands will now properly execute and result in the correct HTTP response being delivered to the client.

Behavior Change