Learning Windows Server 2003

8.2. IIS Components

IIS is not installed by default in new installations of Windows Server 2003, unlike previous versions. You can choose from several "subprograms" that each perform a different service and install them as you need them. IIS is the moniker that refers to all these services collectively. This section will highlight the individual components and provide a bit of information about each.

8.2.1. The Web Server

The web server , named W3SVC , is the part of the software that makes files available for web browsing using the HTTP protocol. You can support multiple DNS domains on one server by using either multiple virtual servers or a feature called host headers. Host headers examine the TCP/IP header of a web request, detect the intended destination of the packet, and route it to the appropriate process; this obviates the need for different domains to have unique IP addresses on one machine.

8.2.2. The FTP Server

This component of IIS (FTPSVC ) enables you to transfer files from a server to a client. The FTP protocol dates back to the beginning of the Internet, and it's still one of the most efficient ways to transfer large amounts of data between hosts over a wide area. However, FTP is inherently insecure because it transfers all dataincluding the username and password for authentication purposesin clear text.

8.2.3. The SMTP Server and POP3 Server

The Simple Mail Transfer Protocol (SMTP) is the protocol widely used to transport mail over the Internet. It's the actual component that pushes mail around from server to server. IIS 5, introduced in Windows 2000 Server, included a functional SMTP server (SMTPSVC) which supported the other parts of IIS and formed the basis of Internet email functionality in Exchange 2000. But out of the box it could only send mail. You couldn't set up a plain-vanilla Windows 2000 Server on the Internet and use it to send and receive email.

In Windows Server 2003, Microsoft has included a rudimentary but helpful and functional Post Office Protocol 3 (POP3) service. The POP3 service serves as the mechanism by which users can retrieve mail from their mailboxes. The POP3 service works, although its functionality is limited and its scalability is questionable. For a small business, it's a free alternative to more expensive commercial email software packages, such as Microsoft's Exchange Server 2003.

8.2.4. The NNTP Server

The USENET news service, full of newsgroups ranging in topics from music to cooking to computers to automobiles and everything in between, runs off the Network News Transport Protocol (NNTP). You can use the NNTP component of IIS (NNTPSVC) to implement a discussion board within your organization if you lack the time or knowledge to use a more complex solution such as Exchange or SharePoint Team Services.