This is an area, which causes a great deal of confusion amongst both webmasters and end user clients. Before we go any further, let's look at this quick analogy: DNS can be considered something similar to that of a phone book. When you move from one location to another, your last name stays the same, but your phone number may change. In order to point your name to the new phone number, you must contact the telephone service provider, which will assign you the new phone number. In addition, they update all directory information data basis to reflect you as pointing to this new phone number.

What is DNS?

DNS stands for "Domain Name Server." The domain name server acts like a large telephone directory in that it's the master database, which associates a domain name such as (http://www.mydomain.com) with the appropriate IP number. Consider the IP number something similar to a phone number: When someone calls http://www.hostinganddesigns.com/, your ISP looks at the DNS server, and asks "how do I contact HostingAndDesigns.com?" The DNS server responds, it can be found at: 157.238.46.231. As the Internet understands it, this can be considered the phone number for the server, which houses the http://www.HostingAndDesigns.com web site.

Where are all of the DNS records kept?

This is slightly more complicated, but for the purpose of this overview, we'll try to keep it as general as possible. There are 2 basic places DNS records reside:

- International Root name servers (13 exist throughout the world)
- Your domain register, where your current DNS settings reside.

When you register/purchase your domain name on a particular "registrars name server", your DNS settings are kept on their server, and in most cases point your domain to the Name Server of your hosting provider. This Name Server is where the IP number (currently associated with your domain name) resides.

The entire hierarchy is somewhat involved, but in short, the world Root Name Servers can be considered the master listing of all DNS records, and there are currently 13 of them in the world. These name servers are where all the master DNS records are kept. The DNS server of your ISP will typically query the Root Name Servers once every 24-hours. This is how they update all of their DNS tables, which in turn, resolve www requests to the IP number of the server they reside on.

Changing your Name Server settings, so your domain points to your HostingAndDesigns account:

Your "Name Server Settings" must be updated to point to your account on HostingAndDesigns. You originally purchased your domain name from a registrar, and this registrar is where your current DNS settings reside. That is, unless you transferred your domain name to an alternate registrar, in which case, you would control your DNS settings from there.

The "registrar" your domain resides on, communicates your 'current' DNS settings with the International Root name servers, which is turn share this information with ISP's, routers, and cache engines around the world. In essence, it's like a worldwide directory that other computers can refer to when they want to match a domain name with its associate IP number. This IP number is how the particular server your website resides on is located.

Accessing your domain manager:

Simply go to your domain registrars web site, and look around for links, which point to something like, domain manager, manage domain, or something of that administrative nature. In your welcoming email (shared hosting accounts only), you were sent DNS settings, which look similar to this example:

NS1.HOSTINGANDDESIGNS.COM
NS2.HOSTINGANDDESIGNS.COM

Most of the newer registrars such as the (OPEN SRS) based entities have turned this into a 5-minute process. You simply login to the registrar, select 'manage domain' and you'll be presented with an option to update your new DNS numbers. Contrary to popular belief, Network Solutions 'now' also provides an online interface to change these settings, so this process with them is no longer as complicated as it use to be, however it's still not as simple as the OPEN SRS based systems.  If your particular registrar 'does not' provide a domain manager of some type, then you'll need to send them a message requesting a change of DNS. This is an unlikely scenario, as most every registrar now allows you to manage your own domain settings from a web based interface.

Once you've accessed the "management interface" of your domain name, look for a setting, which says "change or manage DNS settings." In most cases, you can simply cut and paste the DNS settings we've sent you directly into the spaces, which correspond to your DNS management settings. Remember, the DNS settings we're displaying here are an "example."

The 3 to 4 day propagation period - Understanding what happens during this time frame:

In short, patience is a virtue. Remember what we talked about earlier in this chapter regarding the shear size and scope of the worlds DNS system? In short, when you change your DNS settings, these new settings must propagate throughout the worlds DNS servers. It also means that every ISP (Internet Service Provider), must update their DNS records to reflect these new changes, which in most cases, is done automatically every 24 hours, but not always however...

Where do the Root Name Servers receive their information from?

The Root Name Servers will query "domain registrars" several times a day. Domain Registrars, being entities such as Network Solutions, and the newer OPEN SRS based systems. The Root Name Servers will gather this information from the many registrars now in existence, and update their master records accordingly. Now your ISP must access the Root Name Servers, and update their DNS records, which reside on their 'local' DNS server. This process is fully automated and most ISP's will check the Root Name Servers for updates every 24-hours. Beware however, that some lame ISP's will delay this process for as much as 2 to 4 days in some cases. If that happens, it will no doubt cause additional confusion, as everyone else will be reaching your new account on our servers except you. This is because your ISP has not updated their DNS records, and or have not cleared their DNS cache, which means they'll still be pointing your domain name to your old server. If it's a new domain name you've registered, then you'll receive a blank "Site Not Found Page."

DNS Cache and your ISP:

There is also the issue of DNS cache, which is something we won't go into great detail about here, but here's the short version. Every time you access a site from your ISP, they cache the URL, as well as its associated IP number. If their network is properly setup, these DNS cache records should "Expire" at least every 24-hours. If they did not (which is often the case), you'll experience this: You enter your http://www.mydomain.com/ URL, and it keeps taking you back to your old server account.

In a large number of cases, it's the result of an ISP who "Did Not" configure their servers to "Expire" the DNS cache records at the appropriate intervals. Unfortunately, this adds additional confusion to their clients, and especially the ones whom are trying to point their domain name to a new server. Yes, it will make you want to scream sometimes, however if you understand whom is actually at fault, then you'll know who to scream at :)

The DNS propagation process is not limited to ISP's!

HA.. Just when you thought you had it all figured out! Unfortunately, there's more folks. The Internet itself must update/clear its DNS cache as well. When we say the Internet, we mean the numerous intermediate "points of access" you're routed through before reaching your final destination. For the most part, these intermediate points of access consist of "Internet Routers" and "Internet Caching Engines." These too, maintain their own DNS cache, which assists them in routing traffic/resolving URL's to the correct destination IP's. Don't worry though, as Internet routers are usually faster at clearing their DNS cache than ISP's are.

What to expect during this 2 to 4 day propagation period:

In most cases, the propagation process will take at least 48 hours to complete. The first thing that happens is the "World Root Name Servers" will check all of the various "Domain Registrars for updates. Ok, so now the Root Name Servers have done their job. The rest of it is up to the many ISP providers who "should be" updating their DNS records (at least every 24 hours), but a number of them will not.

Checking your DNS update status (outside of your ISP):

In the event you're becoming impatient, and or are wondering if the rest of the world outside of your ISP can access your new site, you can proxy yourself to another network and test it there. In many cases, you'll be surprised to see your site responding perfectly, yet when you attempt it directly from your ISP's servers, it does not exist.

There are several services, which allow anonymous surfing across the net. While this is not the intent here, they can be used for trouble shooting domain resolution problems. How?  Because they proxy you through their network, which means your URL requests are controlled by "their" DNS cache records. These services update/expire their DNS cache far more often than ISP's, which makes them well suited for testing your domain name through a network, which operates with the latest DNS updates across the web.

To run this check, you can try accessing your site through this services: http://www.anonymizer.com/

This allows you to enter a URL, and proxy your request through their servers. If your site is accessible from these servers, then chances are, your ISP has yet to expire their old DNS cache records.