DNS Propagation Explained - or Why You Have to Wait the 72 Hours
By Andrei A
So you found a perfect domain name that was
not already taken, figured out how to register it, paid for hosting (leasing
space to store all the files that will be publicly accessed as web pages) with a
WHP - aka Web Hosting Provider (such as bsleek.com) and even uploaded your
website to the WHP's servers, or had a professional design firm create a web
site for you.
Alas, it looks like the results of your hard
work, of your money spending and of the headaches you got from trying to make
sense of all the technobabble were in vain? Why can't you see your website
instantly - after all, is't this the promise of the e-commerce age?? Hey, when
they took your credit card payment, that went pretty fast!! Is it that nobody
really cares about customer service anymore? And what is this "propagation"
nonsense those techies are trying to bamboozle you with?
Is your new Web Host Provider a lemon? Did you
make a big mistake chosing it??
All this has to be very frustrating, unless
you understand exactly how things work. Over the next few paragraphs, I will try
to demistify the DNS propagation process, by telling you in plain English, what
DNS propagation is, how it works, and why is it that the only thing we can do to
speed the process up is.... wait.
DNS stands for Domain Name Server. I know the
word Server is intimidating and you are thinking "oh sure, another article
written in technicalese language". Think of a server as a regular computer, like
the one you are using now to read this. That's right! Your beloved computer can
be a server too. We call a computer a server when that machine is up and running
and providing a service ("serving" something, whether a web page, a text
document, etc.)
With the language barier lowered, I will tell
you that DNS can be tricky, especially when first registering a domain name or
transferring your website to a web hosting provider. The strangest things can
happen that would lead you to believe that your new web hosting provider is at
fault.
99.99% of the time the Web Hosting Provider is
not to blame and I will explain why.
There are a number of things involved in DNS
that I will familiarize you with. Sorry, but it has to be done. Again, like
everything else in life, once you understand how things work, things will look
much brighter.
Things you need to hear about are:
- IP Addresses
- Service Providers
- Domain Names
- Domain Name Registrars
- DNS
- The Propagation Process
1. IP Addresses
Our computers talk to each other by
identifying themselves using numerical addresses much like the address on your
home or for your telephone. When one computer wants to speak to another
computer, it all boils down to an address or what we call an "IP Address".
Here is an example: 64.247.43.26
As you would imagine, the number of possible
addresses, while immense to the untrained eye, is actually limited and we are
almost on the verge of exhausting all the numbers.... Here's a piece of trivia
for all interested in cool facts: Typically, service providers (see below)
receive thousands of IP addresses to be used on their networks. IP addresses in
the United States are assigned by ARIN, the American Registry for Internet
Numbers. They are the assigned numbers authority and they control who gets IP
addresses in the US.
2. Service Providers
The service providers will use IP addresses to
identify their network equipment so that they can conduct business on the
internet.
There are many different types of service
providers but for the purpose of this article, I will only discuss two of them.
The ISP (or Internet Service Provider) is the
company that provides you with access to the internet. Without them, you would
not be able to send email or surf the world wide web. When you connect to your
ISP, they will assign your computer one of their IP addresses. This IP address
will be used to identify your computer while you are connected to the internet.
The WHP (or Web Host Provider, such as
bsleek.com) is a company that provides a means for individuals or businesses to
publish a website on the internet. When the website is published, it is placed
on a special computer known as a server that is connected to the internet via a
high-speed connection. The WHP has already assigned this server one of their IP
addresses.
Now, let's summarize what we have learned so
far by looking at a typical internet users experience:
Let's say that you want to surf your newly
published website. You connect to the internet and your computer gets an IP
address (much like a phone number, a license plate, etc) from your ISP. You then
open up your web browser and type in your website's domain name: yourdomain.com.
Then you hit enter. Your computer sends a
request. That request is blasted across the internet jumping through routers and
gateways, across wires and beamed to satellites and back down to Earth again.
After traveling several thousand miles in just a few milliseconds, it finally
arrives at your WHP's web server because it contains the IP address of the
computer you are looking for.
The server then responds by sending a copy of
the website's home page back to your computer because it knows the IP address of
the computer that made the request. You are now looking at your published home
page in merely a few seconds and being proud of the pretty colors you picked for
your menu buttons.
How did this all happen? Read on:
3. Domain Names.
A domain name is what you typically enter into
your web browser when you want to visit a website. We also use them when sending
email.
Website: www.yourdomain.com / Email:
user@yourdomain.com
Domain names provide a fast and convenient way
of reaching our favorite websites and sending email to each other. It is easy to
remember the name of a friend's website or a company that you like to shop with
rather than trying to remember a number like: 64.247.43.26
What are we missing here? The mechanism that
translates numbers into names (that is, IP addresses into domain names) and vice
versa. Suspense....
4. Domain Name Registrar
If you want to have your own domain name you
will need to register one through a company called a Domain Name Registrar. The
domain registrar has tools that allow you to search for and register an
available domain of your choosing. The registrar is more or less at the top of
the whole naming scheme chain.
If you were able to read this far and even
stay focus, congratulations - you ar a very determined individual. And now, as a
reward for reading this much of my article, I will talk about... DNS, which is
the topic you came here to read about in the first place.
5. DNS
DNS is a software program that runs on a
dedicated computer known as a DNS server. DNS serves two primary functions:
1) To translate domain names into IP
addresses.
It's much easier to remember a domain like
mydomain.com than a sixteen digit number like 64.247.43.26. DNS servers make
translating or "Resolving" this information fast and seamless. When your
computer needs to know the IP address for yourdomain.com it asks a DNS server
(usually the one provided by your ISP.)
2) To act as authority for designated domain
names.
Wherever you decide to host your website, the
network you are on must have its own DNS servers. In fact, it is an
industry-wide standard to have at least two DNS servers or more. These servers
will act as the authority for your domain name because your network provider
will put a special entry in their DNS server as it relates to your domain name
that says: YOU ARE HERE! Technically this is known as an "A" record for
"Authority".
There are literally hundreds of thousands of
these DNS machines world wide. They ARE the yellow pages of the internet and
they contain information about your domain name. Keep in mind that no single DNS
server holds all the domain names for the internet; they only hold the names
that they are responsible for, and a few pointers to find the rest.
Some DNS servers strictly store names while
others are doing the work of providing lookup services for computers that need
to look up names. Many DNS servers do both. Technically, the server that is
responsible for a particular domain is called the "Authority". Remember the "A"
record?
There are a few pieces of crucial information
stored in a DNS server with regard to your domain name. This information as a
whole is known as your "DNS Record". In it you can find a variety of other
pieces of information (or records) about your domain name. For the purposes of
not altering your sanity, in this article I will focus only on the domain name,
the ‘A' record (or your WHP's DNS servers).
6. The Propagation Process
As I said before, your domain registrar is the
one responsible for publishing your domain name at the very first (called root)
DNS level. When it is published, it is placed into a directory that is broadcast
out to primary DNS servers around the world.
The primary DNS servers broadcast out to
secondary DNS servers and so on and so forth.
This process is known as propagation and it
can take upwards of 72 hours to complete. Propagation refers to the amount of
time it takes for all the DNS servers everywhere around the world to recognize
the fact that either a new domain is being registered, a domain name has been
changed, or that the authority for that domain has changed.
Other reasons why it takes so long is
obviously the size of our planet and the total number of DNS servers that
require updated information. DNS servers are always updating themselves and
changing dynamically during the course of any given day. When or why one DNS
server will receive updated information before another is a complete mystery -
really!
In most cases, your DNS propagation will
complete well within the 72 hour period but you can't be sure that everything is
fine until you wait out the 72 hours! Once propagation is complete, anyone,
anywhere on the internet should be able to visit your hosted website.
During that time you may experience strange
occurrences. This is because not every DNS server that needs to know, knows
about your domain name. Take your ISP for example. They use two DNS servers,
well, 24 hours after making your nameserver changes, only one of your ISP's DNS
servers might receive the update regarding your domain name and the other might
not.
If only one of these servers can resolve your
domain to an IP address and the other can not, what you will experience would be
as though your website was going up and down. One moment it is there, the next
it is not.
Here is another example:
A friend of yours can see your new website and
you can not. This is most likely because his ISP's DNS servers are able to get
the information at that time, where your ISP's DNS servers can not.and wait
another 72 hours. Ouch!
Here is a neat one:
You are transferring your hosting to a new
WHP. During propagation you are working on development of some pages in your
website. But you notice that when trying to view your most recent changes, they
appear and then vanish or they don't appear at all.
Think about the load-balancing DNS servers
again. One server has information about your OLD WHP and the other has
information about your NEW WHP! This can be a weird experience and may take some
time to figure out. What you really need to do is WAIT OUT THE 72 HOURS!
You see, if you avoid making changes to your
website during a transfer/propagation period, you will always have a consistent
functional website available to your visitors. They won't know that you have
switched WHP's because as far as they can tell, they are just browsing your
website. They won't realize that you are in a state of propagation and that from
one minute to the next, they are potentially browsing your site from two
different WHPs.
All of these occurrences are very common and
each one of them will result in a phone call to the WHP asking why the server is
going up and down. In reality the server is fine and your WSP is one of the
finest. The problem is that the domain owner has not let 72 hours pass by, after
which these and other similar problems will have vanished.
So as you can see, your Web Service Provider
is not at fault, you just must have patience and wait the full three days before
you can try to determine if your website is experiencing a problem or not.
Andrei co-owns bsleek.com (
http://www.bsleek.com ) – a site that
specializes in web hosting, design, promotional items, printing, CD
Presentations and more. Andrei is on the Board of Consultants for Daterade.com
and has amassed an extensive technical knowledge and experience through his
career as the CIO for a major travel management company and through his past
careers in military research, data acquisition and aerospace engineering.
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