Windows NT 4.0 DNS Supports Host Names with Invalid Characters

• Microsoft Windows NT Server versions 4.0

SUMMARY

Host names and domain names are restricted to the following set of characters: 0-9, a-z, A-Z, . (dot), and - (hyphen).

RFC 952 states the following:

1. A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.).

   Note that periods are only allowed when they serve to delimit components of "domain style names." (See RFC-921, "Domain Name System Implementation Schedule," for background.)

   No blank or space characters are permitted as part of a name. No distinction is made between upper and lower case. The first character must be an alpha character. The last character must not be a minus sign or period.

MORE INFORMATION

Windows NT 4.0 Domain Name System (DNS) server does not enforce the name restrictions, and will do WINS lookup for host names containing invalid characters and find them if they exist.

NOTE: It is not recommended to use invalid host names in non-proprietary environments like the Internet. Other DNS servers may have problems with names containing invalid characters.