Caching only nameserver fails to resolve external zones periodically

[Jim Reid]

Your tcpdump trace shows your server making queries. There was no need
to provide ~300 lines of essentially identical output. 4 or 5 would
have been enough. However you didn't run tcpdump properly so we can't
see if your server got any replies back. That means we don't know if
your firewall is allowing your DNS traffic through. If it doesn't,
fix that. If it does, your name server should now be working just fine.