24 May DNS Explained
The purpose of the DNS (Domain Name Server) system is to give client computers a means of translating host names (ex. wpmututorials.com) into IP (Internet Protocol) addresses. In a typical day of working my browser(s) submits hundred of queries to my DNS servers to get the IP address of the web sites I have requested. Once the browser has the IP address it submits my request to that IP address.
DNS did not exist in the early days of the Internet. Originally, what each system admin did was maintain a local list of host names and the IP address associated with each host (in the early 90's I was one of those system admins). When it was a small number of hosts this worked ok. But, as the number of hosts being accessed grew, maintaining the local list became regular maintenance. Every time a service was moved from one host to another, everyone who accessed the service had to update their hosts file.
When you are setting up your DNS, what you are doing is adding the lookup information for your domain to the Internet's DNS system. The types of records that you may have to add are:
- NS - This identifies a DNS server that is an authoritative server for your domain. Other DNS servers will query this one to get the domain's current DNS records.
- MX - This is a record to say where the domain's mail server can be found,
- CNAME - Canonical name - This is essentially an alias that points one domain name to another domain name.
- A - This is an address record and specifies the IP address that the domain can be found at.
The note to keep in mind with DNS is that it is separate and distinct from web, mail, ftp, etc. server setup.