Hi! I have the following network: Internet >> NetscreenFirewall_1 >> ISA 2004 >> NetscreenFirewall_2 >> Internal Network with two Exchange 2003 FE and BE servers and one global catalog. The external clients can access Exchange over OWA/POP3/IMAP4/SMPT without any problem. The same clients can access Exchange 2003 by using RPC over HTTPS only when they have the name of Back-End Exchange name as mail server name on Outlook client. Back-End Exchange name is NOT published by using ISA. Only FE is published. Also the external DNS server has NO RECORD for Back-End Exchange server. Why can the external Outlook client resolve the name of Back-End Exchange successfully? I do not want that the external clients have the name of Back-End EXchange. They should know only the name or IP of ISA Server. Must Outlook clients (RPC over HTTPS) really have the name of Back-End Exchange as mail server? Please only solution tips and information. Thanks. Best Regards Mustafa