F5 iRule

Try this:

when HTTP_REQUEST {
 if { [HTTP::host] equals "192.168.205.151" } {
  HTTP::redirect "http://mycompany/arsys"
 }
}

Assuming that either IP or name will get you to the VIP, you can probably not worry about evaluating that and just redirect based on the URI value. Example:

when HTTP_REQUEST {        
    if { [HTTP::uri] equals "/" } {        
        HTTP::redirect "http://mycompany/arsys"
    }
}