Reading the host header and directing to the corresponding pool

You can check the TCL man pages for details on standard TCL commands:

Click here

For F5-specific commands, check the iRules wiki

Click here

Try this post to start with: Click here

You could combine that example with this one to set the host to lower case before you make the host header comparison: Click here

Putting those together, here's an example which uses switch with the glob flag (for string comparisons). This is less resource intensive than using a regex to do the comparisons.

when HTTP_REQUEST {
   switch -glob [string tolower [HTTP::host]] {
      *example.com -
      *site1.example.net -
      *site2* {
         pool first_pool
      }
      *site3* -
      *site4* {
         pool second_pool
      }
      default {
         pool default_pool
      }
   }
}

You can check the iRules wiki page for switch for details on this (Click here)

If you want to debug this, you could add log statements and check the /var/log/ltm log file. Here's an example for logging:

log local0. "client: [IP::client_addr] matched first switch case"

Aaron