URL redirect/rewrite to external site/header change with internal CA.

 ,

Below iRule will help you to redirect request from external URL to internal URL by keeping brand/<requested-URI> URI part.

Once request is redirected to www.internalworld.com, client will get certificate available on this internal site.

Hope it fulfills your use case.

when HTTP_REQUEST {
 
if { [HTTP::host] equals "www.wallyworld.com"} {
 
HTTP::redirect "https://www.internalworld.com/brand[HTTP::uri]"
 
}
}