Exchange delivery stalls until another message opened

[Sibine]

A client of ours has a problem which has been causing some on-going
grief for us AND them!

They have a Windows XP SP2 client with Microsoft Outlook 2003 in an
Exchange (SBS 2003) environment. When you send the user an email
(internal or external it makes no difference), the email won't appear
in the users inbox until they open another email from their inbox.

Have tried almost every resource so hoping someone can help me out!

Thanks so much

Si.

 

[K. Orland]

This sounds like a UDP issue. This issue occurs because Outlook uses the user
datagram protocol (UDP) to receive new e-mail message notifications, to
update folder views, and to perform searches.

When making an initial connection to an Exchange server, Outlook registers
itself for new message notifications. Whenever a new message is received in
an Outlook user's mailbox, Exchange sends a notification to Outlook using
UDP. This notification is essentially a small flag to the client that a new
message is present and needs to be displayed. When Outlook receives the UDP
notification, it retrieves the message from the Exchange server and displays
it in the appropriate folder (e.g., the Inbox).

New message notifications are intended for Outlook clients that are running
in either online mode or Cached Exchange Mode, and they won't work for
Outlook clients using RPC over HTTPS. In fact, when using RPC over HTTPS,
Outlook does not register for notifications (because it won't be able to
receive them). Instead, Outlook clients using RPC over HTTPS use a polling
mechanism to check for new messages. While polling is initiated by Outlook,
the polling frequency is dictated by the Exchange server. Polling is not new
to Outlook 2003; Outlook 2002 automatically reverts to polling if the UDP
notification fails. However, new in Exchange 2003 is your ability to
configure a polling interval for RPC over HTTPS clients.

Is the Windows Firewall turned on? You may need to create an exception to
allow Outlook traffic. Is the problem with Outlook the same in cached mode vs
not cached mode?

 

[Sibine]

Thanks Kathleen. Very helpful and resourceful.

We will disable the Windows Firewall (client has hardware firewall
onsite anyhow) and will also experiment with the cached mode/not
cached mode. From my previous experiences with this client (same
issue) I tried cached and not cached without much improvement.

Will update you accordingly.

Thanks greatly,

Si.