Simple DNS server in a docker container returns server unknown

its my first time posting here. I am trying to configure a DNS server with nginx so two docker containers. for some reason, when I do nslookup ns.main.com, it is returning server: unknown.

Here is my DNS file

$TTL 86400
@       IN      SOA ns.main.com. hostmaster.main.com. (
                    202      ; Serial
                    600      ; Refresh
                    3600     ; Retry
                    1209600  ; Expire
                    3600)    ; Negative Cache TTL

@       IN      NS      ns.main.com.
ns      IN      A       127.0.0.1

I am doing this locally so I am using the loopback address. when I do nslookup ns.main.com, i get this message:

Server:  UnKnown
Address:  fd28:8d22:2169:0:9221:6ff:feb3:1438

named.config file look like this:

options {
  directory "var/bind";
  allow-transfer { "none"; };
  allow-query { any; };
  listen-on { any; };
};

zone "main.com" IN {
    type master;
    file "/etc/bind/zone/main.com";
};

zone "secondary.com" IN {
    type master;
    file "/etc/bind/zone/secondary.com";
};

What could be wrong here?

This is the tutorial I am following.

https://www.youtube.com/watch?v=GlCloo47p_E&list=PLOLrQ9Pn6cawvMA5JjhzoQrnKbYGYQqx1&index=3&ab_channel=VeryAcademy

I am doing this locally so I am using the loopback address. when I do nslookup ns.main.com, i get this message...

What command are you running specifically? If you simply run nslookup ns.main.com, nslookup will look in /etc/resolv.conf to find a nameserver, which probably isn't what you want.

You can provide nslookup with an explicit server by passing it a second command line argument:

nslookup <name_to_lookup> <server_to_query>

There is one typo in your named.conf; you have:

  directory "var/bind";

When you probably mean:

  directory "/var/bind";

You will also need to ensure that directory exists.

If I deploy your named.conf with the above change and place your zone records in /etc/bind/zone/main.com, then nslookup seems to work correctly:

# nslookup ns.main.com localhost
Server:         localhost
Address:        ::1#53

Name:   ns.main.com
Address: 127.0.0.1

I've made a complete Dockerfile and associated files available here as a demonstration; if you build an image:

$ docker build -t named .

And then run it:

$ docker run --name named --rm -d named

You can verify that it works:

$ docker exec named nslookup ns.main.com localhost
Server:         localhost
Address:        ::1#53

Name:   ns.main.com
Address: 127.0.0.1