Add a note about DNS being required on Windows.

PR:		5451
Submitted by:	Hank Laskey <CAMResearch@aol.com>
Reviewed by:	Ken Coar


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@84275 13f79535-47bb-0310-9956-ffa450edef68