This allows you to add a hostmask to the specified Client Class.
/as client WebMaster mask add *@*.webmaster.com
The mask is in the form of userid@domin *@*.webmaster.com will let anyone on the server from the webmaster.com domain. *@127.0.0.1 will let anyone on from localhost. userid's can be handy to descriminate against which page a user is coming from on the java client, so you could have support@* and sales@* if your java userid was set to support or sales.