The type of records in DNS is particularly useful when we come to troubleshooting or we have problems in searching things on the Internet or searching for etcetera.

Essentially the different types of records we get within DNS are:

an A record, an Address record is actually the IP address, 192.168.1.1. So an address record will be the record that links the name mail.QEDux.co.za to the IP address.

Then we've got an MX record. MX records are mail exchanger records.

When we discussed two MTA's talking to one another, we had an MTA that was talking to a second MTA - perhaps QEDux was talking to the TSF mail server - what would happen is QEDux would ask the DNS for the tsf.org.za MX records (the Mail Exchange record) because QEDux had some mail send to TSF. Once again it's required that the MX record, the MTA, could begin talking to the TSF MTA.

The MX records are quite important because they indicate who we need to talk to, to exchange mail between different domains.

The final one we are going to talk about is the Cname record and Cname records are canonical names and the expression "canonical names" is fancy words for aliases. For example, www.QEDux.co.za might be a Cname for mail.qedux.co.za and what this means is that the web server and the mail server live on the same machine. The web server, www, is just an alias for mail.

Those are the three types of records that we're going to consider when we look at DNS.