Welcome IPv4 user

An IPv6 enabled cPanel server

This is the first in a series of posts about getting cPanel ready for IPv6. The developers of cPanel have claimed that IPv6 is on their roadmap but have as yet not even released an ALPHA with IPv6 capabilities. This is surprising since almost all the underlying services that that cPanel manages already have IPv6 support and many of them are trivial to activate.

cPanel uses bind under the hood to provide DNS. Bind has mature IPv6 support and is the ideal candidate for getting going with a dual-stack cPanel environment.

cPanel is capable of loading AAAA DNS records into DNS zones. These AAAA records are the primary IPv6 DNS records for mapping a hostname to an IPv6 address. This can be done via the 'Edit DNS zone' feature that is available in the WebHost Manager but is not available on the simple DNS editor in the cPanel interface.

Serving AAAA responses is one thing but you also want your DNS server to communicate on IPv6. The first step is to make sure that your server has IPv6 connectivity. This can be checked by loging in via ssh and running the command 'ping6 ipv6.google.com'. Once you are happy that you have a working IPv6 connection you can proceed to the next step:

This step requires that you are the root user on the server. You need to open the file '/etc/named.conf' in your favourite terminal text editor. You then need to add the line

listen-on-v6 { any; };

after the line

options {

You can then save the file and restart the nameserver via the web interface. If all goes well your server will be answering IPv6 DNS queries.

You can test this firstly by doing a 'dig www.mydomain.com @::1' where ::1 is the IPv6 equivalent of localhost. If that works correctly then you want to test a DNS query from another IPv6 enabled host. You know have IPv6 capable DNS servers.


DNS in IPv6 land

Many of the experienced networking people that I speak to about IPv6 have one major complaint: "IPv6 is rubbish - I would never be able to type an address that long out of my head"

It is true that many network technicians and engineers make regular use of IPv4 literals in their daily lives. My view is that if you are typing the IP address then - YOU ARE DOING IT WRONG!

IPv6 may well be the push that is required to get many lazy networking professionals to implement proper DNS on their networks. A properly set up DNS infrastructure even on a home LAN can be a life saver and it save a lot of time in the long run.

DNS tips for IPv6 survival:

  • DNS everything - choose an easy to remember hostname for every device on your network. Every PC, server, router, wifi AP and IP capable device should have a hostname that you can add to your zonefile.
  • Choose your best IP for DNS. DNS should be the only thing that you ever have to manually configure on a device. Choose the shortest and easiest available IP address for your DNS server. If you are running a large network then choose 3 or 4 prefixes that you reserve for DNS anycast resolvers. That way you avoid confusion by using the same DNS server IP throughout the whole network.
  • Keep it local. If you don't want to do full DNS infrastructure then add it to your local DNS resolver. Many home routers and gateways have a 'hosts' facility that allows you to add DNS entries that are visible only within your local network.

and finally

  • Make proper use of 'search domains'. Most IP devices have a config option called a 'search domain' or sometimes just 'domain'. This is the home domain of the host and is appended to any DNS query when it is first looked up. This means that you can use the DNS name 'myserver' and it automatically gets expanded to 'myserver.example.com' for you. This is a huge time saver since your DNS name is now in fact shorter than even the IPv4 address of a host.