DOCUMENT:Q264035  29-JUL-2001  [exchange]
TITLE   :XADM: Can't Configure Port for UDP New Mail Notification Packets
PRODUCT :Microsoft Exchange
PROD/VER::4.0,5.0,5.5
OPER/SYS:
KEYWORDS:exc4 exc5 exc55

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The information in this article applies to:

 - Microsoft Exchange Server, versions 4.0, 5.0, 5.5 
 - Microsoft Exchange 2000 Server 
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SUMMARY
=======

You can configure an Exchange Server computer to use specific Transmission
Control Protocol (TCP) ports for the information store, directory, and System
Attendant to enable access to it through a firewall, router, or other device
that blocks certain TCP or User Datagram Protocol (UDP) ports. You cannot
configure the ports that will be used when the server sends a client a new mail
notification packet. In a situation where UDP traffic from the server to the
client is blocked, clients may not receive new mail notification.

For additional information about configuring TCP/IP access to an Exchange Server
computer through a firewall for Exchange Server version 5.5, click the article
number below to view the article in the Microsoft Knowledge Base:

   Q148732 XADM: Setting TCP/IP Port Numbers for Internet Firewalls

For additional information about configuring TCP/IP access to an Exchange Server
computer through a firewall for Exchange 2000 Server, click the article number
below to view the article in the Microsoft Knowledge Base:

   Q270836 XCLN: Exchange 2000 Static Port Mappings

MORE INFORMATION
================

New mail notification messages are sent by means of UDP packets from the server
to the client. The ports used for this notification are set by the client when
the client logs on to the information store.

As part of the log on process to the information store, the client tells the
server the IP address and port where it expects to receive new mail notification
messages. This will be a UDP port in the 1024-65535 range.

When the server receives a mail message for a mailbox that a client is logged on
to, it opens a UDP port dynamically, and sends a packet to the IP address and
port registered by the client logged on to that mailbox.

Because the client picks a port at startup and the server does not always use the
same port when sending the notification, there is no way to predict either the
source or destination ports that this traffic will use.

For clients to reliably receive new mail notification packets, you must enable
traffic as follows:

   

   Setting          Value
   ------------------------------------------
   Protocol ID      UDP
   Direction        Exchange Server --> Client
   Local Port       >1024
   Remote Port      >1024

The "Client" in this table can be specifying either specific client IP addresses
or the networks where the clients reside. Your filtering device documentation
will have information on how to actually implement the filter.



Additional query words:

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Keywords          : exc4 exc5 exc55 
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2 kbExchange2000Search kbExchange2000Serv
Version           : :4.0,5.0,5.5
Issue type        : kbinfo

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