What is DNS?Posted by Daniel on April 21, 2006
Important: The ability to change the DNS configuration of a web site is an important feature for many people. However, incorrect DNS modifications can take an entire web site down for an extended period of time. This is because DNS changes aren't instant. If you make a mistake, it is possible that nobody will be able to connect to your site (including yourself). If you fix the mistake, it may take up to 72 hours for the repair to take effect.
There are several things you can do to prevent mistakes:
- Review all the help articles available here.
- Make sure you understand what A, CNAME, NS, and MX records do.
- Ask us for additional help and guidance if needed.
- Don't make a major change without assistance.
With a little bit of practice, you will find that making DNS changes is very simple.
Now, what is DNS?
DNS (Domain Name Servers) tell computers how to find each other over the Internet. When you type an address in your browser, your ISP (Internet Service Provider) checks with it's domain name server (DNS) to determine where to send you.
http://www.yourdomain.com ---> Check with DNS ---> DNS says yourdomain.com = 192.168.0.1 ---> You are taken to your web site
Why does this happen?
It happens because your domain name won't always have the same IP address. Each server on the Internet has an IP address (a numerical address like a phone number, in the form 000.000.000.000). If you've transferred from another web host to Slamdot, then your IP address changed because of it.
Domain name servers keep a record of your domain name and what IP address (server) it should point to.
Why must I put Slamdot's name servers (DNS) in my domain record?
As you learned above, name servers tell the Internet how to find you. When you edit the name servers in your domain record, you are telling the Internet which name server provides the most up-to-date directions. If you don't change the name servers in your domain record (let's say you use your old web host's DNS), then your web site will point to a server that isn't hosting your domain. Or, if the old web host deleted you from their DNS, your domain wouldn't work at all.
Why does it take so long for my site to start working?
When you change web hosts (addresses) or register a domain for the first time, the new DNS information has to reach every other name server (DNS) on the Internet. Your site may work in as few as 4 hours, but the average waiting time is 24-72 hours. This delay occurs because most name servers (DNS) choose to periodically check for updates. That is, they aren't "live." Periodic checking is done because constant checking often slows down the server.
Why is my domain pointing to my old host, even though I cancelled my account with them?
There could be several reasons for this:
- Their name servers are still in your domain record.
Solution: Update your domain record with Slamdot's name servers (DNS), which are ns1.slamdot.com and ns2.slamdot.com.
- They haven't removed your domain record from their name servers.
Solution: Same as the above solution.
- DNS propagation hasn't taken place yet. This will happen even with Slamdot's DNS in your domain record.
Solution: Wait 24-72 hours and contact us if the problem persists.
Why can some people reach my new site but I can't?
Their ISP has more up-to-date DNS records than your ISP. Be patient, as your new site will appear within 24-72 hours.
Is there some way to view/access my site even though the DNS hasn't changed yet?
Yes. You may access your site at http://ip.address/~FTPusername and you may access the control panel at http://ip.address/config. To find the IP address and FTP username of your domain, do the following:
From the dashboard, choose a domain...