Running IPv6 DNS Server Inside CentOS Docker Container

To run an IPv6 DNS server (answers IPv6 resolution requests using IPv6) inside a Docker container running CentOS Linux release 7.9.2009 (Core), you can use the following steps:

1. Install the required packages:

docker run -it centos:7.9.2009
yum install -y bind bind-utils

2. Configure the DNS server:

Create a file named /etc/named.conf with the following content:

options {
    listen-on port 53 { 127.0.0.1; };
    listen-on-v6 port 53 { ::1; };
    directory "/var/named";
    dump-file "/var/named/data/cache_dump.db";
    statistics-file "/var/named/data/named_stats.txt";
};

zone "." IN {
    type hint;
    file "/etc/named.root";
};

zone "localdomain" IN {
    type master;
    file "/etc/named/localdomain";
};

Create a file named /etc/named/localdomain with the following content:

$TTL    604800
@       IN      SOA     localhost. root.localhost. (
                        1         ; Serial
                     604800         ; Refresh
                      86400         ; Retry
                    2419200         ; Expire
                     604800 )       ; Negative Cache TTL
;
@       IN      NS      localhost.
@       IN      A       127.0.0.1
@       IN      AAAA    ::1

Create a file named /etc/named.root with the content of the root zone file.

3. Start the DNS server:

named-checkconf /etc/named.conf
named-checkzone localdomain /etc/named/localdomain
service named start

4. Verify the DNS server is running:

docker exec -it <container_id> nslookup localhost

The output should show the IPv6 address of the container:

Server:          ::1
Address:         ::1#53

Name:   localhost.localdomain
Address: fe80::100:27ff:fe64:2125

5. To check the DNS server's status, run the following command outside the Docker container:

docker logs <container_id>

The output should include lines like:

named[13214]: starting BIND 9.11.2-P4+dfsg-1+deb10u2
named[13214]: overall: 0 requests handled, 0 requests rejected, 0 dropped

References:

• BIND 9 DNS Server
• CentOS Docker Image
• Docker: BIND 9 DNS Server
• Docker: Running a DNS Server in a Container

Summary:

• Install the required packages
• Configure the DNS server in /etc/named.conf
• Create zone files for the local domain
• Start the DNS server with service named start
• Verify the DNS server is running and checking its status