What is Recursive DNS
This KB article addresses the basic questions of what is Recursive DNS and how it compares to Custom DNS.
The Short Answer
Recursive DNS is essentially the opposite of Custom DNS. Custom DNS is an authoritative DNS service that allows others to find your domain, and Recursive DNS allows you to resolve other people's domains.
The Longer Answer
Recursive DNS provides recursive DNS. Yes, that's recursive (something which repeats or refers back to itself) and confusing. In order to make a distinction between the service we provide (Recursive DNS) and the general concept of recursive DNS, we'll distinguish between the two by using a heavy font face for our service (Recursive DNS).
To better illustrate how recursive DNS works, lets imagine you are sitting at a computer in your study at home. You're connected to the internet by a cable connection (the actual type of connection is really not important) and you are surfing the web looking for widgets. You have no idea where to find widgets, so you open your web browser and type in
http://www.google.com
This is when recursive DNS kicks in. Your web browser looks to see if it knows where to find the machine "www.google.com". If it doesn't have this info stored in its own cache, it will ask your operating system (OS) if it knows where to find this host. If your OS doesn't have this in its cache, your OS will perform a DNS query to find that info. That query will go to the DNS servers provided by your ISP, and these servers are configured to provide recursive DNS.
To simplify things, the ISP's name server will send a query to the "root" name servers find out who is responsible for the COM domain (i.e. which name servers are authoritative for the COM domain). Once it has this info, it will send a DNS query to those name servers asking them who is responsible for the google.com domain, and then a final query to those name servers asking for the address of www.google.com.
Now, those servers which answer for google.com and resolve www.google.com to an IP address, those are authoritative DNS servers (like our Custom DNS, except we don't provided DNS for Google).
Now, this is where our Recursive DNS service comes into play. Some times an ISP's recursive DNS servers get overloaded and the queries you send to them can start timing out. When this happens, you can't find www.google.com and so you can't search for widgets.
Why are your ISP's recursive DNS servers overloaded? It could be any number of reasons, but it happens. In any case, what we provide is an alternative set of servers that you can use in place of your ISP provided name servers. That's our Recursive DNS service.
If you need something better than your ISP's recursive DNS servers, be sure to try our Recursive DNS service.