added listen on ipv6 addr

named.conf

@@ -12,6 +12,7 @@
 
 options {
         listen-on port 53 { any; };
+        listen-on-v6 port 53 { any; };
         query-source port 53;
 	directory 	"/var/named";
 	dump-file 	"/var/named/data/cache_dump.db";