Managing IMAP4

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Updated : September 4, 2001

from Chapter 13, Microsoft Exchange 2000 Administrator's Pocket Consultant by William R. Stanek.

You use IMAP4 virtual servers to read mail and access public folders on remote servers. Clients can log on to an Exchange server and use IMAP4 to download message headers, and then read messages individually while online.

Most of the tasks you perform with IMAP4 virtual servers were discussed in "Mastering Core SMTP, IMAP4, and POP3 Administration." This section examines the few tasks that are unique to IMAP4.

On This Page

Creating IMAP4 Virtual Servers
Managing POP3

Creating IMAP4 Virtual Servers

When you install the first Exchange 2000 server in an organization and configure it for messaging, a default IMAP4 virtual server is created. The default IMAP4 virtual server allows Internet clients to download message headers, and then read messages individually while online. Normally, you won't need to create additional IMAP4 virtual servers, but you can do so if you want to support multiple domains or build fault tolerance into the organization.

You can create additional IMAP4 virtual servers by completing the following steps:

  1. If you're installing the virtual server on a new Exchange server, ensure that messaging services have been installed on the server.

  2. If you want the IMAP4 virtual server to use a new IP address, you must configure the IP address before installing the IMAP4 virtual server. For details, see "Assigning a Static IP Address" in Chapter 15 of Microsoft Windows 2000 Administrator's Pocket Consultant.

  3. Start System Manager. If administrative groups are enabled, expand the administrative group in which the server you want to use is located.

  4. In the console tree, navigate to the Protocols container. Expand Servers, expand the server you want to work with, and then expand Protocols.

  5. In the console tree, right-click IMAP4, point to New, and then select IMAP4 Virtual Server. As shown in Figure 13-11, this starts the New IMAP4 Virtual Server Wizard.

    Cc722530.exch1311(en-us,TechNet.10).gif

    Figure 13-11: . Use the New IMAP4 Virtual Server Wizard to create the additional virtual server.

  6. Type a descriptive name for the virtual server, and then click Next.

  7. Use the IP address selection list to select an available IP address. Choose (All Unassigned) to allow IMAP4 to respond on all unassigned IP addresses that are configured on the server. The TCP port is mapped automatically as port 143.

    Note: The IP address/TCP port combination must be unique on every virtual server. Multiple virtual servers can use the same port as long as the servers are configured to use different IP addresses.

  8. Click Finish to create the virtual server. If the default startup setting for the Microsoft Exchange IMAP4 service is set to Automatic, the new IMAP4 virtual server will start automatically as well. If the server doesn't start automatically, you may have selected an IP address/TCP port combination that's already in use.

  9. Configure the server using the tasks outlined in this section and the section of this chapter entitled "Mastering Core SMTP, IMAP4, and POP3 Administration."

Allowing Public Folder Requests and Fast Message Retrieval

With IMAP4 virtual servers, you can control public folder and message retrieval in two ways. You can

  • Allow clients to download a list of all public folders or just a list of their private folders.

  • Specify that Exchange Server should approximate message sizes instead of calculating message sizes exactly during transmission.

Both configuration settings can affect the performance of the virtual server. If your organization uses lots of public folders, you'll usually want to disable automatic downloading of all public folder lists. This allows clients to more quickly access their e-mail and private folders. If the IMAP4 server has a heavy load, you can reduce some of the load and hasten the message retrieval process by allowing the server to approximate message sizes instead of calculating exact message sizes.

You set these options by completing the following steps:

  1. Start System Manager. If administrative groups are enabled, expand the administrative group in which the server you want to use is located.

  2. In the console tree, navigate to the Protocols container. Expand Servers, expand the server you want to work with, and then expand Protocols.

  3. In the console tree, expand IMAP4. Right-click the virtual server that you want to work with and select Properties. As shown in Figure 13-12, you want to work with options in the General tab.

  4. To allow clients to download a list of all public folders, select Include All Public Folders When A Folder List Is Requested. Or clear this option to disable automatic downloading of public folder lists.

    Cc722530.exch1312(en-us,TechNet.10).gif

    Figure 13-12: . Use the options in the General tab to configure public folder and message retrieval.

  5. To have Exchange 2000 Server approximate message sizes instead of calculating them exactly, select Enable Fast Message Retrieval. Clear this option to force Exchange Server to calculate message size exactly.

  6. Click OK.

Setting Message Formats

Message format options allow you to set rules that IMAP4 servers use to format messages before clients read them. By default, when Messaging Application Programming Interface (MAPI) clients in the organization send messages, the message body is converted from Exchange Rich Text Format to Multipurpose Internet Mail Extensions (MIME) and message attachments are identified with a MIME content type that's based on the attachment's file extension. You can change this behavior by applying new rules.

Two key aspects of message formatting have to do with encoding and character set usage. Message encoding rules determine the formatting for elements in the body of a message. Only MIME encoding is available. Character set usage determines which character sets are used for reading and writing messages. If users send messages with text in more than one language, the character set used determines how multilingual text is displayed.

To set message encoding and character set usage for an IMAP4 virtual server, follow these steps:

  1. Start System Manager. If administrative groups are enabled, expand the administrative group in which the server you want to use is located.

  2. In the console tree, navigate to the Protocols container. Expand Servers, expand the server you want to work with, and then expand Protocols.

  3. In the console tree, expand IMAP4. Right-click the virtual server that you want to work with and select Properties.

  4. Choose the Message Format tab as shown in Figure 13-13. Then choose one of the following options for MIME encoding:

    • Provide Message Body As Plain Text Exchange Server converts the message body to text format, and any other elements, such as graphics, are replaced with textual representations.

    • Provide Message Body As HTML Exchange Server converts the message body to Hypertext Markup Language (HTML). This allows compliant client applications to display the message body with graphics, hypertext links, and other elements. However, clients that don't support HTML display the actual markup tags mixed in with the text, which can make the message difficult to read.

    • Both Exchange Server delivers messages with their original formatting, which can be either plain text or HTML. Use this option to allow the sender to choose the message format.

    Cc722530.exch1313(en-us,TechNet.10).gif

    Figure 13-13: . You can use the Message Format tab to set per server defaults for message encoding and character set usage.

    Note: Exchange Server also supports a third message encoding. This format is called Exchange Rich Text Format and selecting Use Exchange Rich-Text Format enables it. Exchange Rich Text Format is displayed only when a) clients elect to use this format and b) you've set the message format as either Provide Message Body As Plain Text or Both.

  5. Select the character set to use. The default character set is Western European (ISO-8859-1). All text in the affected messages will use the character set you specify.

  6. Click OK to apply the changes.

Managing POP3

You use POP3 virtual servers to read mail on remote servers. Clients can log on to an Exchange server and then use POP3 to download their mail for offline use.

Most of the tasks you perform with POP3 virtual servers were discussed in "Mastering Core SMTP, IMAP4, and POP3 Administration." This section examines the few tasks that are unique to POP3.

Creating POP3 Virtual Servers

When you install the first Exchange 2000 server in an organization and configure it for messaging, a default POP3 virtual server is created. The default POP3 virtual server allows Internet clients to download mail for offline use. Normally, you won't need to create additional POP3 virtual servers, but you can do so if you want to support multiple domains or build fault tolerance into the organization.

You can create additional POP3 virtual servers by completing the following steps:

  1. If you're installing the virtual server on a new Exchange server, ensure that messaging services have been installed on the server.

  2. If you want the POP3 virtual server to use a new IP address, you must configure the IP address before installing the POP3 virtual server. For details, see "Assigning a Static IP Address" in Chapter 15 of Microsoft Windows 2000 Administrator's Pocket Consultant.

  3. Start System Manager. If administrative groups are enabled, expand the administrative group in which the server you want to use is located.

  4. In the console tree, navigate to the Protocols container. Expand Servers, expand the server you want to work with, and then expand Protocols.

  5. In the console tree, right-click POP3, point to New, and then select POP3 Virtual Server. As shown in Figure 13-14, this starts the New POP3 Virtual Server Wizard.

    Cc722530.exch1314(en-us,TechNet.10).gif

    Figure 13-14: . Use the New POP3 Virtual Server Wizard to create the additional virtual server.

  6. Type a descriptive name for the virtual server, and then click Next.

  7. Use the IP address selection list to select an available IP address. Choose (All Unassigned) to allow POP3 to respond on all unassigned IP addresses that are configured on the server. The TCP port is assigned automatically as port 110.

    Note: The IP address/TCP port combination must be unique on every virtual server. Multiple virtual servers can use the same port as long as the servers are configured to use different IP addresses.

  8. Click Finish to create the virtual server. If the default startup setting for the Microsoft Exchange POP3 service is set to Automatic, the new POP3 virtual server will start automatically as well. If the server doesn't start automatically, you may have selected an IP address/TCP port combination that's already in use.

  9. Configure the server using the tasks outlined in this section and the section of this chapter entitled "Mastering Core SMTP, IMAP4, and POP3 Administration."

Setting Message Formats

Message format options allow you to set rules that POP3 servers use to format messages before clients read them. By default, when MAPI clients in the organization send messages, the message body is converted from Exchange Rich Text Format to MIME and message attachments are identified with a MIME content type that's based on the attachment's file extension. You can change this behavior by applying new rules.

Two key aspects of message formatting have to do with encoding and character set usage. Message encoding rules determine the formatting for elements in the body of a message. With POP3, you can use either MIME or UUEncode. Character set usage determines which character sets are used for reading and writing messages. If users send messages with text in more than one language, the character set used determines how multilingual text is displayed.

To set message encoding and character set usage for a POP3 virtual server, follow these steps:

  1. Start System Manager. If administrative groups are enabled, expand the administrative group in which the server you want to use is located.

  2. In the console tree, navigate to the Protocols container. Expand Servers, expand the server you want to work with, and then expand Protocols.

  3. In the console tree, expand POP3. Right-click the virtual server that you want to work with, and select Properties.

  4. Click the Message Format tab, as shown in Figure 13-15. Exchange Server can format messages using either UUEncode or MIME. To use UUEncode, select UUEncode, and then, if you wish, select Use BinHex For Macintosh to deliver messages to Macintosh clients using the native binary encoding format. To use MIME, select MIME in the Message Encoding panel, and then choose one of the following options:

    • Provide Message Body As Plain Text Exchange Server converts the message body to text format and any other elements, such as graphics, are replaced with textual representations.

    • Provide Message Body As HTML Exchange Server converts the message body to HTML. This allows compliant client applications to display the message body with graphics, hypertext links, and other elements. However, clients that don't support HTML display the actual markup tags mixed in with the text, which can make the message difficult to read.

    • Both Exchange Server delivers messages with their original formatting, which can be either plain text or HTML. Use this option to allow the sender to choose the message format.

    Cc722530.exch1315(en-us,TechNet.10).gif

    Figure 13-15: . You can use the Message Format tab to set per server defaults for message encoding and character set usage.

    Note: Exchange Server also supports a third message encoding. This format is called Exchange Rich Text Format and selecting Use Exchange Rich-Text Format enables it. Exchange Rich Text Format is displayed only when a) clients elect to use this format and b) you've set the message format as either Provide Message Body As Plain Text or Both.

  5. Select the character set to use. The default character set is Western European (ISO-8859-1). All text in the affected messages will use the character set you specify.

  6. Click OK to apply the changes.

from Microsoft Exchange 2000 Administrator's Pocket Consultant by William R. Stanek. Copyright © 1999 Microsoft Corporation.

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