DNS Geeked down… Kelly style

There are guys (!) that I work with that think I shouldn’t cover Geeky topics on this blog… they don’t think people are interested? I beg to differ, I’m interested and I’m confident that if people had the chance to have it explained simply, without all the jargon, then stuff like DNS wouldn’t be so confusing and we’d stop switching off when people started talking about it.

When I first started, DNS was this ‘bunch of numbers’ that all I knew was, if you got it wrong….. everything went down and nothing would work. I went no-where near it for a long time. But as people kept asking me stuff, I decided to check it out. Hence (which is quite common now), I sauntered upstairs into the system administrators world, walked up to the guys and said…. “Guys, this DNS stuff, geek me up!”

We started small, baby steps, one part at a time. After each explanation, I’d make them draw me pictures, go away, saunter back up and ask more questions… pretty soon it had me hooked.

DNS geeks, look away now…..

1) DNS – is short for Domain Name System, it associates various information with your domain name.

We all know what a ‘domain name’ is. Mine for this blog is www.domainpocketbook.com

So, let’s look at my domain name;

The first thing you need to do to look at the DNS (bunch of technical stuff) of a domain name is do a whois (www.who.is), this will give you who the registrant details, provider and basic information that you should need to know.

The parts for this I’m interested in is the ‘Name servers’

Domain Name: DOMAINPOCKETBOOK.COM
   Registrar: REGISTER.IT SPA
   Whois Server: whois.register.it
   Referral URL: http://we.register.it
   Name Server: NS0.PHASE8.NET
   Name Server: NS1.PHASE8.NET
   Name Server: NS2.PHASE8.NET

The ‘Name servers’ are the place that holds all of the technical stuff that is needed to tell the internet where the information associated with your domain is held. So for me, mine is held on 3 different name servers (all of which hold identical copies) ns0.phase8.net ns1.phase8.net & ns2.phase8.net – so why do I have 3 different name servers on my domain? Simple, technology is great, but sometimes things go wrong and it need attention or replacing. If the name server ns0.phase8.net went down, my technical stuff would still be live on the other 2 name servers so everything would keep working as it, this is called in the geek world a ‘cluster environment’. Not all providers use 3 name servers, some use 2 (please never rely on 1), others can go up to 5…

So, lets look take DNS records one by one..

The first part I tackled was the ‘A record’ – in normal language this just means the ‘address’ – this is where your website (hosting) is. You domain name should have 2 A records as a minimum, one for when people type www.domainpocketbook.com into the internet and also one for when someone types domainpocketbook.com into the internet (the one without the www. in front is often refereed to as the blank record).

www.domainpocketbook.com        A           85.233.160.70

domainpocketbook.com        A           85.233.160.70

Most people forget to do both, but it’s becoming more common that people don’t bother typing the www. bit (we’re all too busy). You will find that if people are using ‘Firefox’ as their internet browser, the fact that you’ve forgotten to do both is not that important, as currently it makes the assumption for the customers. However, Google Chrome doesn’t and there is no guarantee that Firefox will continue to do this, better to be safe.

The next thing I tackled was MX records – in normal language this is ‘mail exchange’ – (where your email provider is). Ideally your domain name should have more than one MX record, just in case one of the mail servers you are using is down or busy, most tend to have 3 that I come across.

MX records can be set up in a number of ways, it’s important to know that when you type in the records you never put the www bit before your domain name, this is because in an email address you never have the www …… askme@domainpocketbook.com

Examples;

domainpocketbook.com        MX           Priority 10         mail1.example.com

domainpocketbook.com        MX           Priority 10         mail2.example.com

In this example there are 2 mail servers set up, each with the same priority (10). This means that any emails will ’round robin’ between the two destinations and if one doesn’t work it will go to the other one.

domainpocketbook.com        MX           Priority 10         mail1.example.com

domainpocketbook.com        MX           Priority 20         mail2.example.com

domainpocketbook.com        MX           Priority 30         mail3.example.com

In this example there are 3 mail servers set up, each with a different priority. This means that any emails will first try the one with priority ’10’, it will always favor this one first, if this is busy or not working it will move to the address at priority ’20’ and again if not successful to the address at priority ’30’.

If you have your own mailserver you may put;

domainpocketbook.com        MX           Priority 10         mail.domainpocketbook.com

but then mail.domainpocketbook.com will need to be created separately (this is a subdomain) and that would need an A record….

There are other records apart from A & MX that can be created. This is as far as I went in stage 1 of my ‘geek up’. It’s a good place to stop, so I’ll do the same and later on I’ll tackle the world of CNAME records…. :@)

Special thanks need to go to guys that have made me a DNS geek.. Nathan, James, Ben, JT and Rich.. You had the patience of saints :@)

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