The protocols that Microsoft Exchange 2000 uses to access Web Storage System, such as SMTP, IMAP4, NNTP, POP3, and HTTP, have been redesigned in Exchange 2000 and are now integrated with IIS in Windows 2000. This redesign improves scalability and adds administrative flexibility.
The protocols are administered using Exchange System Manager, rather than Internet Services Manager. Configuration is saved to Active Directory and then replicated to the IIS metabase, on the appropriate Exchange 2000 server, by the Exchange System Attendant.

Exchange Server 5.5 and Outlook already provide native support for Internet messaging and collaboration standards, including Hypertext Transfer Protocol (HTTP), SMTP, POP3, and IMAP. When you install Windows 2000, core Internet protocol stacks, such as SMTP and NNTP, are configured as part of the operating system. Windows 2000 uses these protocols for operations such as directory replication and basic message creation.

When you install Exchange 2000, it extends the core protocol stacks in Windows 2000 with additional command verbs and advanced routing components to provide all of the features required for an enterprise-class messaging and collaborative system.