What is DNS?
DNS internal workings are very complex. However, as far as the end user is concerned, it is actually fairly simple.
DNS is like a telephone book. When you type a URL (domain name) into your browser, or click a link, your web browser searches for the domain name from a table on a DNS server, which finds it and hands your network an "IP address" which is much like a telephone number. An IP address looks something like 111.22.333.44.
The DNS nameservers and IP addresses must match on the server and at the domain registry for optimal website performance.
Common DNS Problems
If you run a "DNS Report" (you can find an excellent DNS report online at dnsstuff.com) Most of the problems you may find will not cause your website not to be found properly. The essential thing to keep in mind is that the nameserver records and IP addresses in the domain name registration match the DNS zone on the server. This is not usually a problem for brand-new web sites, but if you move your website from one server to another, it can be a problem.
Glue at parent nameservers, Mismatched glue error
This means that your registrar probably has your name servers listed incorrectly. This is most likely to occur if you have custom nameservers. Be sure the IP addresses at the domain registry match the IP address on the server. If you have shared hosting and do not have access to DNS on your server, please ask your server administrator for the correct designations. This can also be caused if your domain's TLD (".com" or ".net" or ".org" for instance) does not match the TLD of the nameserver. This will not cause your DNS to fail. But it may cause a tiny bit of slowness. It is usually nothing to worry about.
Missing (stealth) nameservers and Stealth NS record leakage
Your site will most likely run in this condition, but may cause strange results from time to time. This happens when there are nameservers listed in the DNS zone on the server, which are not listed on the domain. This is most likely to happen if the site has been moved from another server. The solution is either:
- If the nameservers are not needed, remove the extra nameservers from the DNS zone on the server.
- If the nameservers belong, you will need to add them to your domain registration.
Lame nameservers or Missing nameservers
This is the essentially the opposite of the Missing (Stealth) nameservers, above.
- You may have forgotten to add a nameserver when you created/ updated your domain registration. Be sure that you have all of the required nameservers properly added to your domain registration.
- Make sure that the nameservers answer authoritatively on the server for your domain. If the nameservers and IP addresses on the server match at the registry and you still have a problem, you may need to ask your server administrator to help.
Missing "A" records
Make sure that each "NS" record on the server also has a corresponding "A" record. This is usually done on the server.
Nameserver Propagation
This is not an actual error. It takes a certain amount of time for nameserver changes at the registry to be noticed by DNS servers worldwide. Propagation will usually start within about 2 hours or even less, and should be complete within 48 hours. If your site continues to behave erratically after 48 hours, you may want to run a DNS Report.
Other Errors
Most other errors you may find will not affect your web site's functionality. If you are experiencing problems, you may have to do more research.
Allen Howard is the senior Technical Support Representative for InfoServe Media, LLC. InfoServe Media is a full service Houston Web hosting and custom website design company. See our website for complete website design and hosting solutions including domain registration and website promotion including Search Engine Optimization (SEO) services and more. Do you want or need to move your web site hosting? Transfer to us and we will migrate your existing site to our server at no charge. |
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