Instant MEssage Polling and Fixed Port Callback Delivery

Instant Message Polling and Fixed Port callback delivery are new connection features available in Microsoft Exchange 2000 Server Service Pack 1 (SP1). These features allow connections between the Microsoft Exchange 2000 Instant Messaging server and the Exchange Instant Messenger client, even if the Instant Messaging server or the Instant Messenger client is protected by a firewall.In Instant Message Polling, the Instant Messenger client polls the Instant Messaging server at regular intervals to check for pending notifications. When a connection is established with the Instant Messaging server, the notifications are delivered. In Fixed Port callback delivery, a single port or range of ports is designated for outbound connections from the Instant Messaging server to the Instant Messager client. Important This paper contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.BackgroundPrevious versions of Exchange did not support polling. The Instant Messenger client sent connection requests to the Instant Messaging server through port 80. The Instant Messaging server then sent notifications to the Instant Messenger client using a random port greater than or equal to 1024. For example, Woodgrove Bank establishes a business partnership with Humongous Insurance to process the insurance needs of Woodgrove Bank