Why DNS Propagation Takes So Long
Many of our tutorials mention DNS propagation delay. You know you need to be patient. It takes 24 to 48 hours for DNS to Propagate so your site is visible. You may also want to explore and check if a problem may exist, delaying the process even further. This tutorial describes DNS and propagation delay and points you to some tools that can help you determine if a problem exists.
What is DNS?
DNS, short for Domain Name System, is the service which translates that domain name you type into your browser into an IP address, and tells your browser which server it needs to connect to to load the site you want to visit. It’s handy because it you had to remember the IP address of every website you visit, it would make surfing the internet much harder.
When a site is set up, as the hosting provider we create a Master DNS record on our DNS servers, which updates any changes made to your DNS records on the server every 15 minutes. You can request that the registrar of the domain point to our DNS server as being the master authority of your domain.
Why Does DNS Take So Long to Propagate?
You have registered your domain name, uploaded your website to one of our web servers, and asked your registrar to either use our name servers or to point your “A” record to your web server’s IP address. Once that this is done, what’s the hold up?
When your website’s address is entered into a browser, the computer requests the IP address of the server housing your site from your Internet Server Providers (ISP) DNS records. If the site is not listed in the records it queries registrars to find out who the DNS start of authority (SOA) is for your website. If you’re using your registrar’s name server as your SOA, it looks up the “A” record for your domain and returns the IP address of the server listed. If you are using our name servers, the registrar points the browser to our DNS servers to determine the IP Address for your domain name. From there the request is sent to the server the domain is hosted on which then provides the browser with the website.
To speed the loading of websites, each ISP caches a copy of DNS records for a period of time, sometimes up to 48 hours. This means that they make their own copy of the registrars’ master DNS records, and reads from them locally instead of making a direct request to the domain registrar every time a request for your site is made. This speeds up web surfing quite a bit by:
- decreasing the return time it takes for a web browser to request a domain lookup and get an answer and
- reducing the amount of traffic on the web.
The downside to caching the master DNS records is because each company or ISP only updates their records every few days, any changes you make to your DNS records are not reflected between those updates. Although our DNS servers update every 15 minutes, the time between updates system wide is not standardized so the delay can range from a few hours to several days. This slow updating of the cached records is called propagation delay because your website’s DNS information is being propagated across all DNS servers on the web. Once completed, everyone can visit your new website.
There are some useful websites which will help you see this propagation process, and show you when your website should be visible:
What’s my DNS? will show you a list of common name servers around the world, and tell you whether or not certain records related to your website have propagated to them.
intoDNS will provide a complete list of your DNS records if available. If records are not yet available DNS propagation has not yet been completed fully.
If it has been longer than 48 hours, your site is not loading, and the two sites above do not show available DNS records, there may be further issues with the configuration of your site. Please contact our support department for assistance with troubleshooting the issue.
Tags: dns, Propagation