DNS Records Information

Technical Documentation

Purpose

Technical Information

DNS records, a Domain Name Server database record type, is used to map a URL to an IP address. DNS records are stored in DNS servers and work to assist users connect websites or other network services to the Internet.

DNS Record Types:

• CNAME Record: CNAME record or Canonical Name record is a type of resource record in the Domain Name System (DNS) specifying the domain name is an alias of or pointing to the IP address of another canonical domain name. For example, a company has a web server with a Static IP address of 192.30.26.110 has been assigned a domain name of ourserver.us.com. A customer has created a website named mywebsite.us.com which has been moved to the webserver ourserver.us.com. The customer wants mywebsite.us.com to be an alias for or pointed to ourserver.us.com. The Static IP address of 192.30.26.110 is also assigned to mywebsite.us.com.
• A Record: An A record or address record is a type of resource record in the Domain Name System (DNS) that is most commonly used to map domain names to an IP address of the computer hosting the domain. For example, if you perform an nslookup for okstate.edu, the ‘A’ record resolves to the IP address of: 139.78.95.107.
• Round-Robin DNS Record: Round-Robin DNS is a load balancing technique of rotating between multiple A Records for the same hostname. Round-robin DNS is often used between a number of web servers to load balance requests. For example, a company has three web servers assigned three different IP addresses housing  identical copies of the same web site having the same domain name.  When users access the domain name or home page, the first user is sent to the first IP address, the second user will be sent to the next IP address, and the third user will be sent to the third IP address. In each case, once the IP address is given out, it rotates to the end of the list. The fourth user, therefore, will be sent to the first IP address, and so forth.​​​​​​​
• MX Record: A mail exchange record (MX record) is a type of resource record in the Domain Name System permitting mail to be sent to the right mail servers located in the domain. An MX record entry has information listed in the order of Host/Server name, TTL value in seconds, Record Type, Data, and MX Level. Ex.: example.com.   1800   MX   mail1.example.com.​​​​​​​​​​​​​​
• SRV Record: A service locator record (SRV record) is a specification of data in the Domain Name System defining the location, i.e. the host name and port number, of servers for specified services. An SRV record entry has information listed in the order of _Service_Protocol_SRV Record FQDN, TTL value in seconds, class, record type, priority, weight, port number, and target. Ex.: _sip._tcp.example.com.   86400   IN   SRV   10   60   5060   bigbox.example.com.​​​​​​​​​​​​​​
• PTR Record: A PTR record points an IP address to a CNAME record or hostname. , but unlike a CNAME, DNS processing does not proceed, returning only the name. The most common use is for implementing reverse DNS lookups. In other words, with the PTR record being the exact opposite of an A record; the PTR address will resolve to the domain name associated with a given IP address.