emphasize a few things about authz_host

- "domain name" is not a good contrast for hostname unqualified, use "partial" as used earlier in the doc
- mention that DNS resolution [of the require line arguments] is done at runtime not startup. This may be
  obvious to developers when you see it uses an ap_expr but the question was specifically asked on IRC.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1903838 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/mod/mod_authz_host.xml

@@ -169,8 +169,9 @@ Require host .net example.edu
     <p>In contrast to the <code>host</code> provider, this provider does not
     rely on reverse DNS lookups: it simply queries the DNS for the host name
     and allows a client if its IP matches.  As a consequence, it will only
-    work with host names, not domain names.  However, as the reverse DNS is
-    not used, it will work with clients which use a dynamic DNS service.</p>
+    work with complete host names that can be resolved in DNS, not partial domain names.  
+    However, as the reverse DNS is not used, and DNS lookups occur at request processing
+    time (instead of startup), it will work with clients which use a dynamic DNS service.</p>
 
     <highlight language="config">
 Require forward-dns dynamic.example.org