How to do a reverse lookup in DNS?

Which type of DNS record is most commonly used in a forward lookup zone?

A CNAME for the primary name and A CNAME to translate the host name into the proper address.

If you have a primary and have a secondary, you can do both.

Is it possible to use both a CNAME and an MX record in the same zone? Yes. Does a CNAME to an MX record have any difference in semantics than a CNAME to a domain name? From the DNS RFCs, the CNAME record is not required to be recursive, but the MX record must be recursive. Do CNAME's require more resource to maintain than A records? Not by default, as the forward lookup will always end up in a "fast" path that has less rules, but if you are using SOA or NS records, they might take longer to compute. Which is more desirable between a "fast" DNS server vs a "slow" DNS server when forwarding query requests from the DNS clients? DNS forwarding is done almost entirely by caching servers, so speed of the server is irrelevant for most purposes. If you are performing large transfers of information, you want a DNS server that will quickly return answer for the query (this would not include DNS lookups for IP address lookup, which is done separately by the DNS clients).

How can I find the IP of a website hosted on a website? DNS lookups work with the IP address directly and will return the proper IP address, but in this case it is best to perform a traceroute (or similar traceroute program) to determine which network level route and subnet the machine in question uses. Once you have this information, there are several options to determine which machine hosts this resource.

What happens when a domain name changes? It is best practice to have all names registered under a company registrar. If you own the name yourself, you should register it on each site directly, just in case you need to perform a transfer and it is easier to find a "new" name. The registration record will contain instructions for you to change the nameservers and IP addresses.

I have a website, hosted on a webserver, that will be moved, but the new site is on a different domain. How can I redirect the web browsers to the new site without having to update my webserver DNS records?

Do you need reverse lookup zone DNS?

I wanted to put the above in a simple easy to understand paragraph.

But I need some help in doing so. If you are interested in reading more on these 2 acronyms - read on, there is another article coming up.

So what is Reverse DNS? A reverse lookup zone file is a map that holds the IP addresses associated with the fully qualified domain names (FQDNs) entered in the web form. The FQDNs are usually automatically entered in web forms but there are some instances where someone needs to enter the name manually or add a name in order to complete a process. Here is an example of a form where someone has filled out the info and has to verify the request using their credit card details to make a purchase.

The red arrows represent the information in this form. In our example, they need to first find the ip address for the hostname. In this instance of Amazon.au it's 174.129.144.20 . Once the IP address is found we can submit the credit card details and confirm the transaction. This would all happen in a web browser without any special software - unless you use some kind of app or extension.

However sometimes a business will offer a service to find the IP address for a web page that they own or provide an extension to perform the lookup for a web form. Such an extension would then save these IP address - hostname maps in a reverse lookup zone on a central website that everyone can access using your browser's address bar.

Here is one of the web forms of our example above on an image browsing website called SmugMug and looking at our example here the red arrow points to the area where we need to put the hostname. This process is how Google reverse maps a domain name to an IP address so if you go to the Google dnslookup tool and enter your website name you see a list of matching IP addresses. Most website owners also create this reverse lookup zone of mapped hostnames so that they can resolve queries from non-registered customers that they have collected contact info for their customer database.

You can easily set up a reverse lookup zone - and as you get more and more contacts you can expand the zone to grow a larger pool of hostnames to query.