Microsoft Exchange 2000 Server Adminstrator's Companion

Outlook Express, shown in Figure 15-4, is a subset of the standard Outlook product. It ships and installs with Microsoft Internet Explorer and is the default mail reader for Microsoft Windows 98. It allows users to retrieve and send mail messages, participate in Internet newsgroups, and access directory information over standard Internet-based protocols. Outlook Express cannot take advantage of most of the collaboration features that Exchange 2000 Server provides, such as native access to public folders and calendaring. Let's look at its three main capabilities—messaging, news reading, and directory service lookup—and see how they differ from their counterparts in Outlook.

Figure 15-4. Outlook Express.

Messaging

E-mail support within Outlook Express is similar to that of the Internet Mail Only option in Outlook: it supports only messaging over the POP3, IMAP4, and SMTP protocols. When Outlook Express interacts with Exchange 2000 Server for retrieving messages, it does so over either the POP3 or IMAP4 protocol. This means that while Outlook Express can use Exchange 2000 Server as its messaging server, it is not a native Exchange 2000 client. In addition, using Outlook Express to access an Exchange 2000 mailbox does not provide the groupware messaging present in Outlook, such as native access to public folders and Outlook forms.

Outlook Express provides support for multiple e-mail accounts, letting users retrieve messages from multiple servers and view them all in a single Inbox. It also allows multiple users to have their own individual identities for messages, contacts, and tasks. Some basic rules functionality is available through the Create Rule From Message command on the Messages menu (Figure 15-5). Outlook Express can impose some client-side rules for handling incoming mail, but you cannot use it to create server-side rules, as you can with the Rules Wizard in the full Outlook 2000 product.

Figure 15-5. Creating a rule in Outlook Express 5.

News Reading

Outlook Express can act as a news reader for Internet newsgroups via any NNTP-compliant news server, such as Exchange 2000 Server. It can access Exchange 2000 public folders as newsgroups over NNTP. However, when using Outlook Express to access Exchange 2000 public folders, you need to consider the client application that created the entry in the public folder. If the entry was created by an NNTP-compliant news reader, such as Outlook Express, all contents of the entry are available to Outlook Express. If, however, the entry was created by a native Exchange client, such as Outlook 2000, access to that entry with Outlook Express (and with any other NNTP-compliant news reader) is really effective only with public folders containing note items. When Outlook Express accesses a public folder as a newsgroup containing any other Exchange message type (contact item, calendar item, journal item, or task item), it shows only the name of the entry and the information found in the notes portion at the bottom of all Outlook message types.

Performing Directory Service Lookups

Many companies on the Internet provide information about various Internet users. For instance, if you wanted to find out the e-mail address of John Smith, it would be possible to query various directory service providers to see if they have any record of his e-mail address or other information about him. Outlook Express makes the directory service queries via LDAP.

Outlook Express does not access LDAP-based information by querying an Exchange 2000 server specifically. Because Exchange 2000 Server relies heavily on Active Directory, an LDAP query would be directed to Active Directory via LDAP over TCP port 389 to seek information about a user. The client could be configured to present any LDAP queries to an Exchange 2000 server or to any domain controller in your Windows 2000 Active Directory. For more information on LDAP, POP3, IMAP 4, and NNTP, see Chapter 17.