How Exchange Users TCP/IP

Exchange clients use Windows Internet Naming Service (WINS) to locate servers.

Exchange servers use the Domain Name System (DNS) to locate other Internet servers and servers that can accept email.

To avoid allocating static IP addresses to every PC, Exchange clients use Dynamic Host Configuation Protocol (DHCP) to take short-term leases on an IP address from a range a DHCP server controls.

Clients often use Remote Access Service (RAS) for dial-up access to systems. RAS uses DHCP to allocate IP addresses to clients as they dial in.

To connect to Exchange via Outlook Web Access, Web browsers need Internet Information Server (IIS). IIS uses WINS to locate other Web servers.

Users can use Network News Transport Protocol (NNTP) to transfer information between public folders and Internet newsgroups.

Systems can use the Secure Sockets Layer (SSL) to secure connections between Post Office Protocol (POP) 3, Internet Message Access Protocol (IMAP) 4, and Web browsers and servers, and to secure Internet Mail Service (IMS) to IMS site connections. (For more information about these topics, see "Related Articles in Windows NT Magazine."

Connecting Exchange to clients or other servers through a firewall requires fiddling with dynamic and fixed IP ports. Some of the articles on this topic in the Microsoft Knowledge Base are "XCLN: How to Force Static Mapping of Sockets" (http://support.microsoft.com/ support/kb/articles/ q155/8/31.asp) and "XCON: Configuring MTA TCP/IP Port # for X.400 and RPC Listens" (http://support.microsoft.com/ support/kb/articles/ q161/9/31.asp).