DOCUMENT:Q146677  21-AUG-2001  [exchange]
TITLE   :Host Names Beginning With Digits Not Accepted in IMC
PRODUCT :Microsoft Exchange
PROD/VER::4.0,5.0
OPER/SYS:
KEYWORDS:kbnetwork

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The information in this article applies to:

 - Microsoft Exchange Server, versions 4.0, 5.0 
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SYMPTOMS
========

If you attempt to use a host name that contains a numerical digit as the first
character in the IMC Properties Connections page, the following error message
appears:

   The host name or IP is not valid.

STATUS
======

Microsoft has confirmed this to be a problem in Exchange Server version 4.0. We
are researching this problem and will post new information here in the Microsoft
Knowledge Base as it becomes available.

This problem has been corrected in the latest U.S. Service Pack for Microsoft
Exchange Server version 5.0. For information on obtaining the Service Pack,
query on the following word in the Microsoft Knowledge Base (without the
spaces):

   S E R V P A C K

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

Exchange Server does not allow a host name to begin with a numeric value for the
following directives in the IMC Properties Connections page:

 - E-mail domain

 - Forward all messages to host

 - Forward all messages for this domain to host

This behavior does not comply with Section 2.1 of RFC1123, which states the
following:

   2.1 Host Names and Numbers

   The syntax of a legal Internet host name was specified in RFC-952 [DNS:4]. One
   aspect of host name syntax is hereby changed: the restriction on the first
   character is relaxed to allow either a letter or a digit. Host software MUST
   support this more liberal syntax.



Additional query words:

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Keywords          : kbnetwork 
Technology        : kbExchangeSearch kbExchange500 kbExchange400 kbZNotKeyword2
Version           : :4.0,5.0
Issue type        : kbprb
Solution Type     : kbfix

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Copyright Microsoft Corporation 2001.