It depends on what version of ISA you are using. In ISA2004, it's as simple as creating a rule for POP3 going ONLY to that one site, and not creating any other rules for POP3 at all. -----Original Message----- From: Vitor Verdura [mailto:cineldoporto@xxxxxxxxxxxxxxx] Sent: Monday, May 09, 2005 13:46 To: [ISAserver.org Discussion List] Subject: [isalist] POP3/SMTP access only to one external ip adress http://www.ISAserver.org Hi, I bought 2 books from Tom Schindler's and I visit many times the site www.isaserver.org. But I have a litlle question: -How can I block access to all external POP3/SMTP address except to one? I spend my intire day working on that but I can't do it... Can you help me? Thanks in advance Vitor Verdura