What is an A record?
Every host on the Internet has a unique number. This is called an IP address and has a notation of four numbers (bytes). The numbers are separated by a dot. An IP address might be 22.214.171.124. This IP address is hard to remember and hard to communicate with your friends or business relationships. To make life easier the Internet uses names, or domain names, to recognize IP addresses. Therefore, instead of 126.96.36.199 we could say www.hongmao21.info, which is much easier to remember. This is very similar to having your very own name listed in the phonebook: your name has a number there as well your phone number. An A record is nothing more then an assignment of an IP address to a name.
What is a MX record?
All the email programs in the world have to know where to deliver email to. This part is also set up in the DNS (the Domain Name Server) and is called a Mail Exchange (MX) of a domain. A mail exchange should be a specified host on the Internet, configured for your domain name. An MX record is the assignment of one or more mail exchanges to a domain name.
What is a CNAME record?
CNAME-records are domain name aliases. Often computers on the Internet have multiple functions such as web-server, ftp-server or chat-server. To mask this, CNAME-records can be used to give a single computer multiple names (aliases). For example computer yourdomain.tk may be both a web-server and an ftp-server, so two CNAME-records are defined: www.hongmao21.info = hongmao21.info and ftp. hongmao21.info = hongmao21.info .