iRule for url redirect for internal application.

Create a new iRule and use something similar to this

when HTTP_REQUEST {
    if { [HTTP::host] equals "help" } {
        HTTP::redirect "https://url/dgg"
    }
} 

(untested, I grabbed an example from here https://devcentral.f5.com/questions/redirect-testexamplecom-to-testexamplecom-abc-def-ghi)

Also make sure that your VIP have an HTTP profile and a client ssl profile with a valid certificate.

If the URL that's redirected to ("url") points to the same VIP as "help", make sure that the certificate used is valid for both hostnames.

Hope it helps.

/Andreas