Troubleshooting IMAP Connectivity in Outlook 2003

Executive Summary:

Microsoft Office Outlook 2003 is equipped to serve as an email client using the Internet-standard IMAP4 revision 1 (rev1) as a protocol, as outlined in Request for Comments (RFC) 3501. IMAP connections pose unique challenges for Outlook, which it doesn’t always meet successfully. At times you might need to troubleshoot IMAP connectivity between your Outlook 2003 client and the IMAP server you’re using. Here are some tips that can help you with such troubleshooting. And in the sidebar, "Getting IMAP To: Field Information in Outlook 2003," I provide a workaround to circumvent an Outlook 2003 IMAP limitation.

IMAP Logging
Outlook can log its communications with messaging servers. To initiate transport logging in Outlook, from the Tools menu, select Options, Other, Advanced Options. Then select the Enable logging (troubleshooting) check box, as Figure 1 shows. (For more information about enabling transport logging, see the Microsoft articles “How to enable transport logging in Outlook” and “How to turn on the Enable Mail Logging option for troubleshooting in Outlook 2003 and Outlook 2007.”)

This function doesn’t discern between protocols or email accounts. If you have multiple protocols in your account settings, enabling this transport logging will generate log files for all protocols across all accounts. POP3, SMTP, and Messaging API (MAPI) protocols are logged in a single file called OPMLog.log, whereas Hotmail connections are logged to Hotmailx.log. You can find the IMAP logs in Documents and SettingsusernameLocal SettingsTempoutlook loggingaccountnameimapx.log. New IMAP log files are created for every Send/Receive action, whether manually initiated or based on schedule frequency and are incremented by 1—for example, IMAP0.log, IMAP1.log, IMAP2.log.

You’ll need to restart Outlook for logging to begin. Be aware that Outlook doesn’t provide functionality to purge logs from these folders as they grow. You’ll need to take additional action to prevent the folders from reaching sizes that impede computer performance, by either manually deleting logs or scripting a solution to do so. If you’re using Outlook 2003 with at least SP1, you’ll see the text Logging Enabled in the window title bar as a reminder to disable this functionality after you’re finished troubleshooting. Transport logging is something you want to implement for troubleshooting purposes only and disable when it’s no longer required.

While logging is enabled, Outlook creates new IMAP logs for each send/receive connection with the IMAP server. When you restart Outlook after enabling logging, you might see a larger file in the logs; this larger file indicates an initial header synchronization. Our sample log, the imap20.log file in Figure 2, shows the type of information contained in a typical IMAP log file. In that file, we can see the initial connection to the IMAP server, a status check on the various subscribed folders, and a LOGOUT and disconnection from the IMAP server. This log file identifies a normal, updated IMAP client.

TCP/IP Packet Captures
You can also use TCP/IP packet capturing or sniffing to troubleshoot IMAP connectivity between Outlook 2003 and its IMAP server. For packet capture, I use the free Wireshark or its predecessor, Ethereal. (Development on Ethereal has stopped, and the project continues under the new name of Wireshark.) Figure 3 shows a typical packet capture (using Ethereal 0.99.0) of an IMAP session between Outlook 2003 and its IMAP server. It identifies the connection and logon and the presence of 5,858 items in the inbox, called EXISTS. You can infer that SSL isn’t used for this example, since the password () is visible.

These two troubleshooting techniques can help you verify connectivity problems between Outlook 2003 and the IMAP server. Although they might not solve your IMAP problems with Outlook, they can show possible issues in the client/server session. Once you've identified such issues, you’re well equipped to delegate more troubleshooting to your ISP or administrator. For more information about IMAP, see “RFC 2060: Internet Message Access Protocol - Version 4 rev1.”