Why do we use username and password in Healthcheck Monitor ?

WAY back, as a customer, I ran my LDAP through my BIG-IP 6400s. That is a feature that allows you to test authentication as a portion of your monitor. If the SLAPD manager password changes, or such, everything breaks.. but that can also be a good thing. If someone has changed your SLAPD manager password w/out your awareness, you become aware VERY quickly! 🙂 Also, as noted by Nikoolayy1, you do not NEED to do this with a TCP monitor. I just thought I'd expand on WHY you might want that: to test the protocol fully with a search in your monitor.