For the less technical
(Skip ahead if you already know the basics) DNS (Domain Name System) is a method of taking a computer and giving it a name on the web. For example our domain is 7rocks.com. I might have a laptop which I’ve called Manfred. To access it from anywhere in the world we’d like to type manfred.7rocks.com maybe in a web browser to access web software on manfred.
7rocks.com comes to this website, but manfred.7rocks.com connects to the hypothetical computer called manfred. For technical reasons when the computer is on your home network you need something called dynamic host resolution to make this happen.
For the more technical
Sniffing around Bind9 trying to make my own dynamic DNS service I realised that Bind9 has a service called NSupdate. I’m not sure if it was there in the early naughties when I was setting up mail and DNS servers, but it’s here now. So the scripts I wrote are minimal and there’s no more hand editing of the zone files. Fantastic!! Especially if you’ve a server with a static IP address already. Nice one Bind9. The O’reillys books are still good for giving an overview of how it all works for those interested in giving it a crack.