If you are new to the world of DNS then you may want read our "What is DNS?" tutorial at the following URL before you start troubleshooting: http://about.hover.com/dns101

DNS problems can prevent you from being able to load a website or connect to other online services.

If your registered domain isn't resolving, you may receive a page cannot be displayed error or a default search page when trying to reach your domain in a web browser on your computer.

Most DNS problems are caused by outdated records in a DNS cache. If you've recently changed your domain's DNS records, or pointed your domain at new name servers, it may take anywhere from 15 minutes to 48 hours for your Internet Service Provider (ISP) to update the DNS cache on their name servers. In these situations, once the ISP's DNS cache is updated, your problem will be fixed. Updates to cached DNS records are processed automatically at regular intervals.

We'll start by summarizing the DNS troubleshooting steps.

Step 1: Gather Information

a. Determine the IP address the domain name is pointed to according to its authoritative name servers.
b. Determine which IP address your computer is using for the domain name.

Step 2: Try to Fix the Problem

a. If the your computer is not using the IP address listed in the authoritative name servers for the domain name, then it is a DNS issue. If there have been recent changes to the domain's name servers or DNS records, then the problem is most likely due to caching by your ISP, or you may be able to fix the issue by flushing your computer's DNS cache.

b. If your computer is pointed at the same IP address for the domain name as the domain name's authoritative name servers, then it is not a DNS problem. Browser cache or errors in the domain's DNS records could be to blame.

The first thing that has to be done when troubleshooting any kind of DNS problem is to determine what name servers the domain is pointed at and what DNS records exist on those name servers.

Log into your Hover account, select the List of Domains tab, then click on the domain name that is experiencing problems.

Go to the Manage Domain tab then click on Name Servers. These are the authoratitive name servers for the domain, meaning they are the primary source for DNS records for the domain name.

If the name servers are set to ns1.hover.com and ns2.hover.com, then click on Manage DNS.

Alternatively, if the domain is not pointed at our name servers, then you can skip to the section titled "DNS Dig."

Select the Click here link under Manage DNS.

The Manage DNS section will show you all of the DNS records that are on the Hover name servers for your domain name. These records have no effect if your domain name is not pointed at Hover's name servers.

The records we are going to focus on are the A records. The A records control where the domain is pointed for web hosting and URL forwarding purposes. The MX record (Mail Exchange record) controls where incoming email is delivered.

In the example above, the blank record (@) is pointed at 64.99.80.30 and the wildcard record (*) is also pointed at 64.99.80.30. This is the default IP address for Hover. Any Hover domains that are using our domain forwarding services need to be pointed at 64.99.80.30. If your domain is hosted with a third party hosting company, you should expect to see a different IP address in your A records.

The blank record points awesomelawncare.com at 64.99.80.30 and the wildcard points www.awesomelawncare.com and <anything else>.awesomelawncare.com at 64.99.80.30.

If you are not using Hover's name servers, then a dig will show you your current DNS records. Step by step instructions for performing a dig can be found here: http://about.hover.com/dig

Checking name servers, the Manage DNS section in your Hover account, and the DNS dig have provided us with information on where the domain is pointed according to its authoritative name servers. Next, we need to find out where your computer is pointed by doing a name server lookup. Click on the appropriate link below for step by step instructions:

Windows Users: http://about.hover.com/nslookup

Apple Users: http://about.hover.com/nslookupmac

Linux Users: http://about.hover.com/nslookuplinux

A failed name server look up may return an unkown host, non-existent domain, or a similar error message. If this happens then it is a sure sign that there is a problem with the DNS resolution of the domain name.

Several Internet Service Providers (ISPs) employ a practice of DNS hijacking or DNS redirection to direct their customers to a search page when a DNS look up fails. As a result, instead of returning a DNS error, the ISP returns their own IP address to redirect you to a page of advertisement links.

More information on DNS hijacking and ISPs who have started this practice can be found in the following Wikipedia article: http://en.wikipedia.org/wiki/DNS_hijacking

So far we've just been gathering information to narrow the scope of the problem. You should now have these two important pieces of information:

1. The A record IP address from the authoritative name servers for the domain name.
2. The IP address your computer is using to load the domain's website (or an unknown host error message).

Compare the two IP addresses. Are they the same or different?

If the IP addresses are different, or if you receive an unknown host error message, go to Step 2 (a). If the IP addresses are the same, scroll down to Step 2 (b).

If your computer is not resolving an IP address for your domain name, or the IP address does not match the records from the authoritative name servers, then we have a problem with the DNS resolution of your domain name. The problem could be with your Internet Service Provider's DNS servers or your computer's DNS cache. We can eliminate your computer's DNS cache from the equation by flushing your local cache. Click on the appropriate link below for step by step instructions:

Windows Flush DNS Cache: http://about.hover.com/flushdns

Apple Flush DNS Cache: http://about.hover.com/flushdnsmac

Linux Flush DNS Cache: http://about.hover.com/flushdnslinux

If your computer is still not resolving your domain name, then I suggest contacting your Internet Service Provider for further assistance.

As mentioned near the beginning of the tutorial, DNS caching can cause Internet Service Providers to report an outdated or incorrect IP address for your domain. This problem usually fixes itself within 48 hours. You can visit the following website to check the IP address that several different ISPs are using for your domain: http://www.whatsmydns.net/

In the example above, you can see that an ISP in Moscow wasn't able to return an IP address for awesomelawncare.com. Their customers may have experienced DNS problems when trying to visit http://awesomelawncare.com, at the time that this article was written.

If your domain name is pointed at the same address resolved by your computer, then the problem is not due to DNS resolution. It is most likely a problem with your web browser. Clearing the temporary Internet files from your web browser may fix the problem. A step by step tutorial is located here: http://about.hover.com/clearcache

DNS experts: Make sure you haven't edited the hosts file in your operating system. Your computer will use the IP address in the hosts file before querying external DNS. If there is an incorrect entry in your hosts file, the DNS resolution will never work. If you are not a DNS expert and you haven't manually edited your hosts file, then you don't have to worry about this. This is a hidden system file.
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