If dnsquery has to mount /srv/dns, it doesn't do it quite correctly:
	term% unmount /srv/dns /net
	term% ndb/dnsquery
	can't open /net: '/net' dns: permission denied
	term% ndb/dnsquery
	> 

Reference: /n/sources/patch/applied/dnsquery-mount
Date: Tue Sep 28 23:15:53 CES 2010
Signed-off-by: miller@hamnavoe.com

--- /sys/src/cmd/ndb/dnsquery.c	Tue Sep 28 23:14:00 2010
+++ /sys/src/cmd/ndb/dnsquery.c	Tue Sep 28 23:13:58 2010
@@ -34,7 +34,7 @@
 			print("can't mount(%s, %s): %r\n", srv, mtpt);
 			exits(0);
 		}
-		fd = open(mtpt, ORDWR);
+		fd = open(dns, ORDWR);
 		if(fd < 0){
 			print("can't open %s: %r\n", mtpt);
 			exits(0);