So you have found your domain name, registered that new domain name, and paid for hosting to store all your sites pages ready to be served to your site's visitors. What comes next?
Well we need to point that domain name to the server at your hosting provider where your web site is stored. Firstly DNS stands for Domain Name Server. The word server may sound a little intimidating to begin with, but this is not the case, a server is any computer that is providing a service, even your own computer can be a server. We call a computer a server when it is providing a service such serving web pages, video files, or any other of the multitude of things that can be served by a computer.
Now that you understand what a server is, and that the term server is not something to be intimidated by, we can move on to why configuring your DNS can be tricky when initially registering a domain, or transferring your site from one hosting provider to another. When setting up your DNS sometimes odd things can occur, and usually your first port of call is your web hosting provider, but 99% of the time the web hosting provider is not to blame, below I will explain why.
To explain DNS you need to familiarize yourself with a few things first, once you have an understanding of these things you will be able to better understand how DNS works.
The following things are what you need to know:
IP Adresses Service Providers Domain Names Domain Registrars DNS The Process of Propagation
1. IP Addresses
Computers communicate using numerical addresses, these addresses are used to identify each computer connected to a network, much in the same way as your phone is tied to your phone line. When a computer on a network wishes to communicate with another it uses this numerical address to connect to the computer it wants to communicate with. It is this numerical address that is known as an IP Address.
2. Service Providers
Service providers use these IP Addresses for indentifying their network hardware, these addresses allow them to conduct their business on the internet.
There are countless types of service providers but for simplicity we will only need to discuss two types of providers.
Your ISP (Internet Service Provider) is the business that supplies you with access to the internet. When your modem connects to the ISP, your ISP will assign your computer with an IP Address. This IP Address is then used to identify your computer while connected to the internet.
The Web Hosting Provider is a company that provides storage and the associated networking hardware to businesses or induviduals to allow them to publish their web sites on the internet. When a web site is published it is placed on a server that is connected to the internet, this server also has an IP Addresses assigned to it.
To help explain what we have learned so far, I will give an example of what typically occurs when an internet user connects to a web site.
For example you wish to view your newly published web site. Firstly you will connect to your ISP, then your computer is assigned an IP address by your ISP, next you open your browser and type in your web site's domain name and you hit enter.
Next your computer send a request, this request travels across the internet through many different networks, through routers and gateways until this request finally reaches your web server.
The web server then replies to this request by sending the contents of your home page back to your computer. As the server knows the IP address from which the request came, it knows to send the contents back to the address assigned to your computer, and now you are looking at the web page.
How does this occur?
3. Domain Name
Typically when you want to view a web site, you enter the domain name into your web browser. Domain names are also typically used when checking or sending an email, for example, for a website you would enter www.yourdomain.com, for an email you would use user@yourdomain.com.
Domain names are a friendly and convenient way for reaching our favorite web sites and sending email. Domains names allow us to use names we can remember, it is much easier to remember www.google.com than 204.154.45.187.
Now I guess you are wondering how the domain name we enter into our browser translates into the IP Addresses we talked about earlier and vice versa. Enter the....
4. Domain Name Registrar
If you want your own domain for your web site, the domain name registrar is where you will purchase the domain name. The domain registrar will usually have tools to help you find an unregistered domain, and once you have found the domain you wish to use, you can purchase a domain registration. The domain name registrar is the party at the top of the domain naming tree so to speak. Now that we have learned the above things we can move on to what this article is all about, the DNS.
5. DNS (Domain Name Service)
The DNS is a of software application that runs typically on a dedicated computer known as a DNS Server. The DNS server has two primary operations.
1 - Translate Domain Names to IP Addresses.
Remember earlier I mentioned that domain names are easier to remember than IP addresses, this is where the DNS does it's job, it translates domain names that you enter on your computer into IP addresses, once your computer knows the IP address of the computer it wishes to communicate with. When you connect to the internet typically your computer is given an IP address, also during the creation of this connection your ISP will typically pass on a DNS server address for your computer to use to "resolve" any domain names you enter while using your computer.
2 - Act as an authority for domain names.
When you purchase web hosting for your web site, the hosting provider will have its own DNS servers. These servers act as an authority for your domain name. When you setup a domain with your web hosting provider they will add a record to their DNS server that basically says "This Domain is Located Here!". The technical terminology for this is an "A Record", with the A standing for Authority.
Around the internet there are many thousands of these DNS servers, basically serving the same function as phone book, they keep a list of all domains in use and the IP address that is tied to each and every domain name.
6. The Process of Propagation.
Firstly your domain name registrar is responsible for publishing you domain name at the very top DNS level (techincally known as Root). When the domain is published, it is stored in a directory and is then broadcast across the internet to primary DNS server located all around the world.
The next phase is the primary DNS servers broadcasting your domain name out to secondary DNS servers and so on.
The process of broadcasting domain names out from the top level (Root) DNS to the secondary DNS servers is known as propagation and it can take upwards of 72 hours to complete. The term "propagation" refers to the time it takes for all the DNS servers world wide to recognize a newly registerd domain, or that a change to an existing domain has taken place.
Typically DNS propagation will take less than 72 hours but you cannot be sure that all is well until you wait out the 72 hours. Once the process of propagation has completed, any person, anywhere in the world should be able to visit your web site at your hosting provider using your domain name.
While propagation is in progress it is normal to see strange things occur, this is because not every DNS server that needs to know your domain name, actually does yet. Commonly during the propagation process, it can appear that your web site is going up and down.
This is due to some DNS servers knowing your domain record, while others do not and can often result in needless calls to your web hosting provider asking about your server going up and down when the fault does not lie with the server itself, but infact lies with the person who registered a new domain or changed an existing domains record, and not waiting at least 72 hours before testing that all is well with your new hosting provider.
Hopefully I've now armed you with the information needed to understand why you have to wait 72 hours for DNS propagation to occur, and it should save the embarassment of calling your web hosting provider only to be told that the problem is not with their server but with DNS propagation.
Article Written By David J. Smith, owner and operator of Webhost-Advisor.com