Warning: We’re about to get kinda techie here. . .
We sometimes have clients that are unable to access their website from their office, but it works fine at home. With employees returning to their offices soon, this may come up again. If this happens to you, your office may have LAN Based DNS.
What is DNS?
The Domain Name System (DNS) translates domains to the numerical IP address of the web-server that provides the website or other service. When you connect to www.google.com, that gets translated to 18.104.22.168, which is (currently) the address of the computer that serves their website to you. This makes the internet much easier to use. Imagine having to remember the IP address for every website that you wanted to connect to!
When loading a website, your computer will need the IP address for the web-server. To do this, your router will refer to your Internet Service Provider (ISP), which then connects to the authoritative name servers, also known as Root Servers. The Root Servers are hundreds of computers spread throughout many countries. They tell your ISP which Nameserver to use to get the records it needs. Your ISP then connects to that Nameserver to translate the domain that you typed in, to the IP address for the web-server. Although this entire process happens quickly, your ISP and computer will cache (save) this information so that it can cut down the process the next time you visit that domain.
LAN Based DNS
LAN Based DNS is common in offices that want to be able to use their domain in unique ways, only available to those in the office itself (or through a VPN). The process is similar to using Public DNS except that everything happens within your office and is maintained by your IT department.
When loading a website, your computer will need the IP address for the web-server. To do this, your router does not refer to your Internet Service Provider (ISP) like it normally would. Instead, the translation is stored locally (somewhere on your office network). It connects to the office Nameserver to translate the domain that you typed in, to the IP address for the web-server.
QUICK TIP When launching a new website. . .
If your office uses LAN Based DNS, it will also need to be updated when launching a website on a new web-server. Otherwise, the public may see the new website and your office will see the old website!
Testing for LAN Based DNS
This is a quick test that you can do if you are having trouble loading a website from within your office.
Connect to your office wifi on your mobile device and load a random website. If it loads, your wifi has access to the internet. If it fails, let your IT department know.
If your office has access to the internet, try to load the website that you are having trouble with. If it fails, disable wifi on your mobile device and load the website again. If it loads when wifi is off and fails when you are connected to your office wifi, then there is something wrong with your office network. Contact your IT department and let them know what is happening.
If you are unable to load the website whether your wifi is on or off, there could be a problem with your website. Contact your web host and let them know what you experienced.