Host Names Beginning With Digits Not Accepted in IMC (146677)

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.