(For instructions about when and how to return control of the virtual servers to the Internet Services Manager snap-in, read the Microsoft article "XADM: Exchange 2000 Setup Removes SMTP and NNTP from Internet Services Manager" at Before you use the Exchange System Manager snap-in to make changes to the protocol virtual servers, make sure you understand how the IIS metabase (which holds information about the protocol virtual servers) synchronizes with Active Directory (AD—which holds routing and other configuration information).
SMTP's basic approach to mail exchange was satisfactory in the Internet's early days, when people sent only short and rudimentary text messages.
Today, though, people often need to send huge messages to long distribution lists (DLs)—and fast.
Enabling SMTP capabilities on a Win2K server doesn't take much work on your part.
During Win2K installation (or during an upgrade from Internet Information Server—IIS—4.0 to IIS 5.0), simply configure IIS 5.0 to include SMTP and Network News Transfer Protocol (NNTP).
A protocol virtual server combines an IIS protocol stack, an IP port number, and an IP address.
The default SMTP virtual server combines the SMTP protocol stack, port 25, and the host server's IP address.
This transition marks a fundamental increase in Exchange's SMTP support.
If you're considering migrating to Exchange 2000 or have already begun to use it in your organization, you'll benefit from learning how Win2K and Exchange 2000 implement SMTP.
The Pipelining extension also increases message throughput.