DNS Problems When a Website "Goes Live"

One of scariest moments in making a site live is making the changes to the DNS records. Because these records ultimately point the whole world to the email and website related to the domain name, a mistake can completely "break" access to the site and email. Because of the way modifications are implemented, if a mistake is made there is no instant way of fixing it. This is because of how domain name servers work.

There are millions of DNS servers in the world. Anyone can set up a DNS server, we have one through RackSpace. Every DNS server contains a long list of every domain name in the world and their corresponding records. These DNS servers have to keep track of lots of information. Domains change all the time and so DNS servers must update themselves frequently. How frequently? That's the kicker. It's up to the system administrator who runs the DNS server. Some update every few hours and others perhaps daily. Therefore, when a change is made to a DNS record it may take a day, or sometimes two, for all the DNS servers to update themselves, thus making the change complete. During this time some DNS servers will point to the new server, and others that haven't been updated will point to the old server. One effect of the DNS update process is that it is entirely possible for users in one part of the world to be accessing an updated DNS server so that they see the new site, while others who access an un-updated DNS server may still be directed to the older site's server.

Because of the way DNS records are updated mistakes can be costly. If the www records or the email records are not modified correctly (misspelling of a domain, or accidentally transposing numbers in an IP address) the new modification will result in updating all the DNS servers with the wrong information so that the website will not be found, and email bouncing. Correcting the record itself can be done very quickly, but the correction won't fully take affect for a day or more.

Additionally, because there is usually more than one party involved in DNS modifications, and information between these parties can sometimes be misunderstood or incorrect, problems with DNS modifications are not uncommon. And again, the more parties that are involved the more delay there can be in making domain record modifications.   next >