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Q194952: XADM: Statically Mapped Port Limitations for Exchange Server

Article: Q194952
Product(s): Microsoft Exchange
Version(s): 4.0,5.0,5.5
Operating System(s): 
Keyword(s): 
Last Modified: 18-JUN-2002

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The information in this article applies to:

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

This article details the limitations involved when statically mapping ports for
the Exchange Server services. In particular, it is recommended that ports which
fall into the ephemeral range not be assigned statically on the Exchange Server
computer.

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

Ephemeral means: short-lived, or not permanent. This name is given to the port
range from 1024 to 5000.

The system will assign ephemeral port numbers to processes as processes request
them. If some process is using the statically assigned port when the Exchange
Server service starts, the Exchange Server service will not be able to use that
port later. The information store and the directory service will still register
all of its other endpoints, and start successfully.

If static entries are needed for the customer's configuration, the following
guidelines are recommended:

- Select ports just above 5000

  -or-

- Select a port number in the 4900 - 5000 range. Programs almost never use the
  ports at this high end of the ephemeral range because ports are typically
  taken from the low end of the range first.

  -or-

- Select ports just below 1024.

  NOTE: The issue is with the use of "well-known ports." To make sure the port
  selected below port 1024 is not in conflict with another process, see Request
  for Comment (RFC) 1060.

Mapping to ports from the low end of the ephemeral range is possible, but
programs that use ephemeral ports choose them at random, typically starting at
the low end of the range, and may conflict with the ports that you have manually
assigned Exchange to use.

Additional query words:

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Keywords          :  
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2
Version           : :4.0,5.0,5.5
Issue type        : kbinfo

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