DNS terms

Posted on 2004-11-27
Last Modified: 2007-02-12

I'd greatly appreciate if someone could give me a quick run down on a few DNS terms? Answers in here would be preferred but if know of any good links please post.

PTR - used for reverse lookup zones. So you can do nslookups?
A records - maps host name to IP

Question by:dissolved
    LVL 95

    Accepted Solution

    Hi dissolved,
    > PTR - used for reverse lookup zones. So you can do nslookups?
    Yes, this helps with NSLOOKUPs as well as validating your system isn't faking it's name/address.

    > A records - maps host name to IP

    > CNAME ?
    Essentially an Alias to an A record.

    > SOA ?
    Start of Authority - best described here:

    > nameserver?


    Author Comment

    Much appreciated leew.

    a-re cnames ever used in conjuntion with MX records?

    -When/how is SOA and nameserver used? Would you mind giving a brief description?

    LVL 95

    Expert Comment

    by:Lee W, MVP
    Hi dissolved,
    > a-re cnames ever used in conjuntion with MX records?

    They could be.  If you registered your mail server as "" but wanted people to access it as "" you would create a CNAME for mail to god.

    > -When/how is SOA and nameserver used? Would you mind giving a brief description?
    Sorry - I'm not quite sure how _I_ can describe this - but here's another link that might help you:

    LVL 2

    Assisted Solution

    SOA is placed on the dns servers which are serving particular domain and only on those servers, when You receive a response from that kind of servers you have an authoritative response if you will receive a response from any other server you have an non authoritative response, cached by the server. The zones are edited only an the servers which are authoritative for particular domain.
    MX record is pointing to the mailserver serving mail for a pointed domain, and you could use mx if you need two domian names for a mail server

    Author Comment

    Authorative servers. What is the difference between them and non-authorative?
    thanks guys

    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    Why You Should Analyze Threat Actor TTPs

    After years of analyzing threat actor behavior, it’s become clear that at any given time there are specific tactics, techniques, and procedures (TTPs) that are particularly prevalent. By analyzing and understanding these TTPs, you can dramatically enhance your security program.

    Don’t let your business fall victim to the coming apocalypse – use our Survival Guide for the Fax Apocalypse to identify the risks and signs of zombie fax activities at your business.
    Join Greg Farro and Ethan Banks from Packet Pushers ( and Greg Ross from Paessler ( for a discussion about smart network …
    After creating this article (, I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
    Here's a very brief overview of the methods PRTG Network Monitor ( offers for monitoring bandwidth, to help you decide which methods you´d like to investigate in more detail.  The methods are covered in more detail in o…

    779 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    16 Experts available now in Live!

    Get 1:1 Help Now