Types of DNS records

If you have a website and often communicate with your host’s support/sales team, I bet you’ve been told at lest once to change some records for your domain. Since not many of you are familiar with the DNS system, I will try to briefly explain some common records, which you will most likely have/use for your hosting account. The most common types of DNS records, most of which every domain name uses are:

1. A
2. CNAME
3. MX
4. NS
5. SOA
6. TXT

Now let’s see what each of these does and why do you need it:

• A

This the IP address of a domain name or the IP address of the server, where the website for this domain name is hosted. For example, the A record of top-web-solutions.com is 207.44.147.74. This means, that each time I type in top-web-solutions.com in my browser, I am taken to a server, which as the 207.44.147.74 IP address assigned. The A record can also be used for subdomains and the subdomain’s A record can differ from the A record of the domain just as each subdomain’s A record can differ from the other.

• CNAME

This is short of cannonical name and is basically an alias. This record is most widely used to point a domain name to an external service (such as blogger.com for example). An easy example of the CNAME in top-web-solutions.com is www.top-web-solutions.com. When we do a CNAME lookup for www.top-web-solutions.com, we see, that the www. subdomain is actually a CNAME record and is an alias (pointing to) top-web-solutions.com.

• MX

This stands short for mail exchange. In other words, this is the record in your domain name’s DNS zone, which points to the mail server for your domain name. Unlike other record types, MX records ca have prioriry. It is used to determine the first mail server, to which your messages will be delivered. If it fails, the second one will be attempted. The lowest nuber here has the higher priority and 0 is the highest. Usually, the more backup servers you have, the better, but in the case of MX records, the best solution will be to only have one. If you have several (lets say 5) MX records and respectively servers in your domain name’s DNS zone, it is very likely to end up with your messages scattered across 5 different servers and it sometimes can be really annoying to gather emails and sort them. Since email is never lost (it is either delivered, delayed or returned to the sender), the most convenient setup is to have a single MX record, so all your messages will end up on the same server.

• NS

This is the type of record, which shows the authoritive nameservers for a domain name. For example, if a domain name has ns1.top-web-solutions.com as an NS record, this means, that this is the authoritive server for this domain and queries for other records should go to ns1.top-web-solutions.com.

• SOA

This is the most vital part of a DNS zone, although, most users never even see or use it. This is used by server administrators to configure a domain name’s DNS zone variables, such as e-mail address for the zone administrator, the zone’s serial number, how often it it updated and so on. From a client’s point of view, this doesn’t have much to do with hosting, but if an administrator hasn’t configured this correctly, it is very likely to expect issues with your domain name.

• TXT

Well, you guessed it, it is a text field :) This section is used to setup some additional parameters for one of the record above. It is most commonly used to add SPF records. In theory, SPF records should add some extra spam protection for your entire domain name, but unfortunately, it only works if both servers (yours an the one, from which some one is attempting to send spam) have SPF set up. Even though it is not as wdely used as we would like, it is still a good idea to have such record.