Authentication irule to calculate authentication response time

This is doable via an iCall Script and Handler combination. An icall script is essentially a TMSH script. Click here for more on iCalls.

The script first sends a GET /servicemon and analyzes the response. If code 1, then it sends a POST (to the URI specified as the form action) with username1 & Password1, if code2 send username2/password2. In both cases the response can be analyzed by the same iCall script and the log updated accordingly.

To finish the job, you would use a "Prepetual" iCall Handler. The handler is like a daemon which runs periodically and executes the iCall script.

There are other ways to do this via an external script and a cron job but, the setup would not be saved with the BigIP configuration.

Note, iCalls are possible as of 11.3 but full support is in 11.4.