If you own a website you may hear talk of Domain Names, DNS, Name Servers etc, so its helpful to have a basic understanding of what they all do. This isn’t intended as a technical explanation, but more as a simplification explaining the minimum you need to know.
Sometimes all of the below will be controlled by the same person/company such as your domain registrar, at other times these could be distributed across several services.
Your domain name is the top of the tree, this is the human friendly way of referring to a server on the internet, rather than using an IP (internet protocol) address such as 220.127.116.11 which is actually Google.com.
Whoever controls the domain name, can change the name servers to point to a different place, but if they point to a different place they cannot change the individual records.
Name Servers or DNS (Domain Name System) change the friendly name into IP Addresses, so that when your visitor types your web address or email address they end up in the right place.
Whoever controls the name servers can overwrite the below, but cannot necessarily change the above.
In order to make sure the right kind of traffic ends up in the right place name servers contain multiple records, that direct different types of requests to different places.
MX Records say who controls your email, this could be your web host, Office 365, Google or something else.
A Records say where your website is and will point to the actual IP address of the web server, multiple A Records can be used to set up sub domains that can be hosted in different places. For example domain.com may be with hosting company A, while intranet.domain.com was with company B.
You would normally see 2 records for each domain, one for www.domain.com and one for domain.com
WARNING : Changing any of the above without fully understanding the set up can result in services stopping working, this could involve websites going down, email bouncing back or literally any thing that uses your domain breaking.