DNS Basics
Author: David Boutcher (http://www.badbison.com/)
This page will give guidance on how to set up DNS records in ISPConfig3
We will assume you have followed this guide to have ISPConfig3 acting as your name server
http://www.howtoforge.com/how-to-run-your-own-name-server-with-ispconfig-3-and-fast-hosts
http://www.howtoforge.com/ispconfig_dns_providerdomain_schlund
http://www.howtoforge.com/ispconfig_dns_godaddy
According to howtoforge Admins, DNS is one of the most common errors in getting servers working. I think this is probably down to poor understanding of what DNS does. So here’s my way of understanding DNS which may help you too.
When you type into your browser http://www.howtoforge.com your browser doesn’t actually know where this site is hosted. Our computers find their way around the internet using IP addresses (internet protocol). So what it needs to do is find the IP the server that howtoforge.com is hosted on. So it knows the site has a top level domain name (TLD) of “com”. So you browser goes to one of it’s designated DNS servers (it already knows the IP of theses) and may get sent to a top level DNS server, although it’s possible that DNS may know the answer. So the message then gets sent to the top level server and will be told, “I don’t know the IP address of that domain name, but I do know a name server that does.” It knows that in this case the primary name server is ns10.projekfarm.com. How does it know this? You will tell the registrar what the name servers are when you register a domain name.
In the example above where the Schlundtech guide was followed, you will have given it a glue record for the name server. So it will know that domain name records are held on ns10.projekfarm.com. Because of the glue record, it also knows the IP address of prejeckfarm.com.
So with that information it sends you to the IP address of projekfarm and looks for the name server ns10.projekfarm.com. Along with other records, that name server holds what’s called an ‘A Record’. This gives out that IP address of the server for that site. So you now go to that IP address and ask the question to the web server, “I’m looking for the site howtoforge.com and I believe it’s held on your IP address.” Presuming everything is straight forward with no complicating factors, that web server dishes out the website that you were looking for.
How does this apply to ISPConfig3?
With a standard setup as in the guides above, we get to the point described above where you were sent to ns10.projekfarm, at this point your server would say, “Acually I host that site.” and it would give out it’s very own IP address. This is because the on a standard ISPConfig3 setup the same machine runs a web server and DNS records. Clever huh!
What if I didn’t follow the Schlundtech name server guide as above?
Well then you’ve missed half the fun of the project, but you can get around this. The chances are, when you registered your domain name, most registrars also provide a DNS service, so you’ll have to instruct it at this point to use a different name server. It’ll be something like ns1.livedns.com. You’ll then have to go into their DNS control panel and make the records, pointing it to your web server with ‘A records’. This might be the better option if you just want to add a couple of domains.
So how do I actually do this?
Follow this link to setting up your first site, it should run you through the DNS Wizard and how to add your first site.
What about email?
Email works very similar, it passes through a series of services directing it to eventually get to your server. MX records are used for email.
Is this really all true?
I’m a lay person putting this into lay person language that I have learnt from experts. My DNS story only follows as near to my best understand of DNS. If anything is incorrect then feel free to correct it or submit your own article explaining it better. My advice is follow the guide to setting up the perfect Debian ISPConfig3 server. Then register a domain name with and follow the Schlundtech guide as above, setting up a glue records pointing toward your own server IP. Then register another domain, give it the new name server details as per your own ISPConfig3 server. Then use the ISPConfig3 DNS manager to add the DNS records pointing to your own IP.
The Schlundtech guide is for ISPConfig2, but is fairly easy to adapt for ISPConfig3. You can also adapt the guide for other registrars native to your country or otherwise. I’ve used UKReg.com that provide glue records that were fairly easy to set up.
If all this fails, then I suggest your next port of call is ask the experts on the howtoforge.com forum. They’re normally willing to talk you through your set up. Remember though that these experts are volunteers on the project and can’t hold your hand every step of the way. Have some confidence in yourself and try work things out for yourself under their guidance. If you want even more assistance, you can find support that your can pay for on the forum.