DNS Info. please help

[Dawiz]

Hello everyone. I am currently learning about DNS and troubleshooting techniques for a job I am hoping to get. I know very little so please be easy on me I need to know the following
1. finding authoritative name servers
2. how to use nslookup(or dig) to look up specific zone records ( A, and/or MX ) from the authoritative name servers
3. I also need to know about DNS caching and why its important to look up DNS answers from the authoritative name server.

if you could help me out with any of these, it would be greatly appreciated. thankyou.

 

[TheEmperor]

Hello everyone. I am currently learning about DNS and troubleshooting techniques for a job I am hoping to get. I know very little so please be easy on me I need to know the following
1. finding authoritative name servers
2. how to use nslookup(or dig) to look up specific zone records ( A, and/or MX ) from the authoritative name servers
3. I also need to know about DNS caching and why its important to look up DNS answers from the authoritative name server.

if you could help me out with any of these, it would be greatly appreciated. thankyou.

Nslookup Info:This page has all of the NSlookup syntax you could want.

DNS Caching is what happens when a DNS server is not configured to relay your DNS request to the Authoritative name server. The DNS is stored on the server for a period of time before being refreshed, which can lead to an incorrect DNS entry being on the DNS server. This is why it generally takes 24-48 hours for changes to your DNS information to change.

The authoritative name server is the one that ALWAYS has the correct DNS. It's the server that the initial change is made on and from which that change propogates. So it's the server that has authority over that DNS information.

Hope that helps.