I took a working name server running bind 9 and fiddled around with the
named.conf file. Then, because I wanted to be able to do further work
remotely, I created a link /etc/rc2.d/S20ssh pointing to ../init.d/ssh) so
it would run sshd when it boots. I copied the sshd_config file from the
other name server we have (which already had sshd running).

Now, although I can ping the name server from anywhere, I can only get DNS
lookups or ssh sessions from a machine on the same subnet. Access from
elsewhere just times out.

netstat shows that the machine is listening on TCP port 53 on the eth0,
hosts.allow and hosts.deny have no entries other than comments. I am not
sure if my named.conf changes have caused the problem or if it is because
sshd is running.

I am hoping that I have made some blindingly obvious novice mistake, so I
won't burden you in this post with config files, logs etc.

Can anyone throw some light on why I have restricted access to the server?