We have an F5 BIG-IP load-balancer we use in front of a web application hosted by several identical servers. The application listens on port 443 for SSL/TLS requests and port 80 for http requests. However, the only thing that happens to an http port 80 request is that it gets a 302 redirect response.

I am trying to create a monitor for the F5 pool used for port 80 that detects that the service is working properly, i.e., that http requests get redirected to https. However, I cannot find a monitor to do this.

Is there such a monitor?

  • Let the F5, rather than the back end servers, perform the http to https redirect and you won’t need the http pool at all (and no monitoring either)... – HBruijn Sep 21 '18 at 22:33

To check that a redirect happens, create a monitor of type HTTP, set the send string to GET / HTTP/1.0\r\n and the receive string to 302 Found.

As far as I can tell, the HTTP monitor type adds a single \r\n because it intends to work with HTTP 0.9, but there's no way to send a redirect in HTTP 0.9, so you have to use 1.0, which requires another \r\n.

To check the destination, try a receive string of Location: https://, possibly with the specific hostname you're interested in appended.

  • That worked (although in my case I had to change 302 Found to HTTP/1.1 302). – user35042 Sep 30 '18 at 20:58

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