Outlook New Message Notification - Windows Firewall
I set up a new desktop for myself at work recently with Windows XP and Office 2003. I hadn’t installed SP2 for XP on my previous machine as I hadn’t fully tested it yet in our corporate environment. This time round I decided to bite the bullet and install SP2 as a colleague of mine had installed it on his machine and hadn’t had any problems.
After I had been using my PC for a few weeks I noticed that there was a delay receiving new messages in Outlook. If I opened another message I would quite often receive a few messages at the same time. It would also take up to 60 seconds for messages to be visible in by Outlook inbox if I wasn’t actively using Outlook. I wasn’t using cached mode and was therefore a little baffled as to why there was a delay.
After a bit of searching a came across an explanation. Exchange sends a UDP packet to the Outlook client when a new message is delivered to the mailbox. When the Windows firewall is enabled the UDP packet gets blocked and therefore Outlook has no way of knowing that there is a new message. When this happens Outlook reverts to polling the Exchange server every 60 seconds.
To allow the packets to reach Outlook you can create an exception for outlook.exe in the Windows firewall. Another method is to create an exception for the UDP port. The UDP port that Exchange uses to send the notification is dynamic; it is issued by the Outlook client when outlook opens. There is however a registry key that can be set for Outlook 2003 so that it uses the same port each time.
I read a few articles and discussions about this issue. The following link contains allot of relevant information with links to the Microsoft articles that describe which registry keys to modify to set a static UDP port for the notifications.
http://listserv.vt.edu/cgi-bin/wa?A2=ind0408&L=techsupport&T=0&F=&S=&P=21999