IT Learning | Server | Secondary DNS

Everything might be not exactly correct in this article but it’s very useful for beginners to understand IT terms. If you want to learn IT but you don’t have any experiences to work in IT industries, I wish it helps you to understand IT and you like to study IT more.

Let’s start our 3 minutes lesson!

What is Secondary DNS?

Secondary DNS is Authoritative name server.
Secondary DNS is a spare server for primary DNS.
Secondary DNS has the same zone file which primary DNS has.

1. Secondary DNS is Authoritative name server

Secondary DNS is actually Authoritative name server.

Secondary DNS has some roles, but it’s mainly used as a spare server for a primary server. So Primary DNS shares the contents of the zone file with Secondary DNS.

What is the zone file and Authoritative name server is here:

IT Learning | Server | Authoritative name server | Japan Teams

IT Learning | Server | Zone file | Japan Teams

1. The role of Secondary DNS

There are two DNS servers. One is Caching DNS and another is Authoritative name server. Usually computers(such as your laptops, servers) ask Caching DNS to find IP addresses of domain names. If Mr. Caching DNS doesn’t know the answer, he asks Ms. Authoritative DNS the question.

**Mr. Caching asks Ms. Authoritative the question.**

Then Ms. Authoritative answers as long as she knows.

**Ms. Authoritative answers an IP address.**

Usually there are two Authoritative name servers just in case one is broken. So the secondary DNS has the same information which the primary DNS has. What kind of information is the same? That’s the zone file, they have the same zone file.

From Mr. caching DNS both of them are same. Nothing is different. So Mr. caching asks the secondary DNS when primary DNS doesn’t answer.

**Secondary answers when Primary can’t answer the question.**

2. What is different between Secondary DNS and Primary DNS?

If they have the same zone file, then what is different? Firstly humans decides which DNS is primary, and humans give the zone file to the primary but not the Secondary DNS.

How does the secondary get the zone file then? Ms. primary gives it! When humans edit the zone file, Ms. primary also tells Ms. secondary what is changed.

**Ms. Primary gives the copy of zone file to Mr. Secondary.**

Did you understand the secondary DNS? Here I talk like the secondary DNS is only one, but actually there are sometimes more than two secondary DNS servers. But they are all same. You can call all of them “Secondary DNS”, and the role is the same. In short, Secondary DNS server is the spare server for the primary DNS server.

You can check more details here :

What is Secondary DNS? Different DNS configurations. (cloudns.net), Name server – Wikipedia, What Exactly Is Secondary DNS? (ns1.com)

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Windows 2000 Dns Server (Network Professional’s Library)