how can I do this...

[AngelDrago]

Hi everyone, how can i do it so when people wants to check there emails so it goes to let say webmail.hisdomain.com with out the https://www.mydomain.com:81/roundcube and still utilizing roundcube...

[larwilliams]

Sounds like an Apache mod_rewrite rule is needed. Unfortunately, I forget the syntax. I think this should work. Put it in the Apache Directives field on the Basis tab for the web site in question

 RewriteEngine on 
 RewriteCond %{HTTP_HOST} ^webmail\. [NC]
 RewriteRule ^/(.*) http://%{HTTP_HOST}:81/roundcubemail/$1 [R]

Edited: forgot to account for you using roundcube instead of the other one.