My old server was dying, so I backed everything up, bought a new server, installed a fresh Virtualmin*, and restored the backups (the old server was Virtualmin too). I touched little else apart from Webmin / Servers / BIND DNS / Update records to change every record from the old IP to the new, and rsyncing archive files – not config files.
Almost everything seems to work as expected – eg apache works, the virtualmin interface on 10000, ssh of course, etc – but, while the DNS server answers correctly when the query is run inside the server (server# dig @localhost mydomain), it does not seem accessible from the outside: other_machine# dig @myserver mydomain times out, from any other domain. In fact, the results are the same with a simple telnet on port 53: it works from inside, but not from outside. (telnet: Unable to connect to remote host: Connection refused). Including when the outside is another server by the same provider (OVH, France).
This suggests to me that port 53 is blocked somehow. I don’t see it there:
#iptables -nL | grep 53
ACCEPT tcp – 0.0.0.0/0 0.0.0.0/0 tcp dpt:53 ctstate NEW
ACCEPT udp – 0.0.0.0/0 0.0.0.0/0 udp dpt:53 ctstate NEW
Nor do I see why restoring backups might have blocked it.
I’m at a loss here. I wonder if the DNS server was blocked before I restored my backups, but the only way to be sure would be to reformat, and I really would like to avoid that. (And at best it’d tell me whether the backups are responsible, not what’s wrong, so that I can fix it).
Keeping in mind that I’m not knowledgeable at all about that web stuff, is there something obvious that I have missed ?
Operating system Debian Linux 9
Webmin version 1.870 Usermin version 1.720
Virtualmin version 6.02 Theme version Authentic Theme 19.04