I have one user on our network who has a new Windows XP Pro with Outlook 2002. Her Outlook will not notifiy her of new messages. To find out if she has new mail, the user has to open another message or switch folders. Her Outlook will also not send an email until she clicks out of the current folder. It will just sit there in her Outbox. I have other users that have Windows XP Pro and Outlook 2002, like me, who don’t have this problem. One user was having problems with a long delay in the time it took to show an email in the preview pane. We solved this by unchecking Enable Instant Messaging in Tools/Options/Other. We use Exchange 2000 on a Windows 2000 server. The client machines are behind a firewall along with the Exchange server so nothing should be interferring. I found some info in MS article # 305572. This is what it says:
This problem can occur in a NAT environment because Outlook 2002 never receives the UDP (Universal Datagram Packets) that the Microsoft Exchange Server sends, and you cannot route the UDP packets to a computer that is running Outlook 2002.
The computer that is running Outlook 2002 returns to polling the Exchange Server for new e-mail messages by using the Remote Procedure Call (RPC) to work around this problem. However, a logic error exists with the Exchange Server and it does not reply to the polling request.
I just don’t think this applies to us because the clients should contact the Exchange server using the internal addresses and shouldn’t go through our firewall or router or NAT.