network-programmingdnsbindbind9

bind9 does not answer to external requests on IONOS VPS

I have a bind9 server running for requests for i.example.com. When I do a request from the nameserver to its own public IP like this nslookup ns1.i.example.com xxx.xxx.xxx.xxx I get the expected answer:

Server:         xxx.xxx.xxx.xxx
Address:        xxx.xxx.xxx.xxx#53

Name:   ns1.i.example.com
Address: xxx.xxx.xxx.xxx

If I do the request from an office computer I do not get any answer:

C:\Users\user>nslookup ns1.i.example.com xxx.xxx.xxx.xxx
DNS request timed out.
    timeout was 2 seconds.
Server:  UnKnown
Address:  xxx.xxx.xxx.xxx

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to UnKnown timed-out

Nmap shows me that port 53 is accessible from the office computer:

PORT   STATE         SERVICE
53/udp open|filtered domain

In my bind9 options I am also listening on my public IP address:

dnssec-validation auto;

listen-on-v6 { any; };
listen-on port 53 { 127.0.0.1; xxx.xxx.xxx.xxx; };
allow-query {
        any;
};
allow-recursion { any; };

Also, I do not have any iptables rules set up.

Any ideas how to fix this?

Solution

  • My VPS provider IONOS has its extra firewall besides my iptables rules. Opnening port 53 in the administration panel did solve the problem.