URI Rewrite

By using "string tolower," you're automatically converting the host and URI to lower case. Since your "eq" statement compares it to "Citrix" and "XenApp" which contain upper case characters, you'll never match.

Give this a shot.

when HTTP_REQUEST { 
if {[class match [IP::client_addr] eq internal_net] and [string tolower [HTTP::host]] eq "www.csg.xyz.com" and [string tolower [HTTP::uri]] starts_with "/citrix/xenapp/" } {
HTTP::redirect "https://csg.xyz.com/citrix/xenapp1/" } }

I used "starts_with" instead of "eq" so we'd redirect people even if their exact uri didn't match...you can also use "contains" here if you like.

This should redirect internal clients from "http://www.csg.xyz.com/citrix/xenapp/" to "https://csg.xyz.com/citrix/xenapp1/"