What is DNS and Why You Should CareOctober 6th, 2011
What is DNS (Simplified)?
DNS stands for “Domain Name System” (or often incorrectly referred to as “Domain Name Server”) and is the service that assigns and directs where and how a domain name’s websites are hosted and email service is handled.
DNS has often been compared to a phone book* for domain names. It’s a giant index of the virtual address (IP Address) for each domain name’s website, email and other resources.
DNS is the service that “points” you to the correct server when you type a web address in your browser or an email address in your mail client.
*Phone books are actual books that old people use to find phone numbers to places like Walgreens and the VFW.
Who keeps track of all this DNS information?
It’s appropriate to think of DNS as a single database. However that database is dynamic and does not exist in one physical location, it’s virtualized . . . in other words it exists only in “cyberspace” and the physical information is redundantly maintained and physically spread across multiple locations throughout the world. (No, the illuminati are not involved.)
There are actually lots of places that DNS records are stored and kept updated but the primary places or services that keep the major indexes of DNS information are:
- Walmart (just kidding)
- One of 13 International Top Level DNS Root Servers (OK, maybe the illuminati are involved after all)
- ICANN domain registrars. This would be the company with whom you have your domain name registered / DNS services through.
Facing the “P” word—Propagation
Propagation is a word internet professionals like to use to confuse others and make themselves look smart. It also is a term that simply refers to the update process that occurs when a domain’s DNS services are modified. Propagation is the time and process that your DNS service provider (likely your domain registrar) takes to update their information and send that updated information up the line to the Top Level DNS servers so that everyone in the world will get to the correct new server when they type in your web or email address.
Propagation creates much angst in the world because it can cause Websites and email services to do strange things and even go offline for a time. It causes angst amongst Web professionals because when a DNS change is made we cannot guarantee to a client how long or exactly what kind and to what extent service interruptions might be. It typically takes 24-48 hours for propagation to complete. Oftentimes it goes through much faster and sometimes, technically, it can take up to seven miserable days (something I’ve never seen personally).
Propagation is a lot like death, taxes and Britney Spears songs . . . as much as we would like there’s no avoiding them and, in all fairness to propagation, it’s not nearly as bad as the other inevitables. The best course of action is to go into a DNS propagation period in an orderly fashion hand in hand with your developer—schedule for a slow time and have the correct expectations (Also, don’t yell at your Web guy because he has no control once the change is submitted. He also is more sensitive than you might.).
To learn more fun facts about DNS and propagation and to know how to prepare for DNS propagation check out our other article:
To have your eyes glaze over and be lulled into a peaceful slumber, consider these reviewing these more technical explanations of DNS: