Hi Joseph, Is the Exchange Server in the DMZ? I don't see why outbound access to the RPC port mapping would be required otherwise. Is the Exchange domain located in the DMZ? If not, things will get very sticky. I'd put the Exchange Server behind the back-end ISA firewall and allow secure Exchange RPC inbound past both ISA firewalls. HTH, Tom www.isaserver.org/shinder Get the book! Tom and Deb Shinder's Configuring ISA Server 2004 http://tinyurl.com/3xqb7 MVP -- ISA Firewalls -----Original Message----- From: josephk [mailto:josephk@xxxxxxxxx] Sent: Thursday, September 02, 2004 3:59 AM To: [ISAserver.org Discussion List] Subject: [isalist] Back to Back RPC for exchange and SMTP Relay http://www.ISAserver.org Hi there, Been working on mail systems since I seem to be attacked by unknown's. Decided to setup Exchange RPC. I also have an SMTP relay. Have the rules for: 135 TCP Outbound 1025 - 65534 TCP Outbound On both my ISA boxes in the back to back. Also, external ISA is forwarding to a mail relay in the DMZ That talks with the back end exchange box. Sometimes I see rpc rules listed in log but, nothing is returned. It is not consistent so I can't really tell what is going on. Yup still running ISA 2000. What conflicts can Anyone see in this type of setup? Thank you, Joseph ------------------------------------------------------ List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ ------------------------------------------------------ Other Internet Software Marketing Sites: World of Windows Networking: http://www.windowsnetworking.com Leading Network Software Directory: http://www.serverfiles.com No.1 Exchange Server Resource Site: http://www.msexchange.org Windows Security Resource Site: http://www.windowsecurity.com/ Network Security Library: http://www.secinf.net/ Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com ------------------------------------------------------ You are currently subscribed to this ISAserver.org Discussion List as: tshinder@xxxxxxxxxxxxxxxxxx To unsubscribe visit http://www.webelists.com/cgi/lyris.pl?enter=isalist Report abuse to listadmin@xxxxxxxxxxxxx