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Basic Questions

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  • Basic Questions

    Hi all,

    There are two things that I need some help on first is there a command via which I can come to know that a client machine and a user are in which OU.

    Second, when we say that port 53 is used for DNS here I would like to know what exactly TCP 53 does in the background and UDP53 does in the background. Is there a link or a website that I can refer to which gives me specific information about all the TCP/UDP ports and their specific functions.

    Thank you in advance.

  • #2
    Re: Basic Questions

    specifically with DNS, it uses UDP for general client queries, and only uses TCP for zone transfers.
    and basically what it does is listen for incoming connections. when it receives a connection, information will be requested from the name server daemon. A reply will then be issued one way or another, to the client. If you would like more specific information about the UDP streams, try using Wireshark or Netmon - this will captuire the info for you and you can see it.
    You could also try this -

    dsquery may help you find which OU a user is in.. try dsquery user -name "DisplayName"Please note this command will not give you exactly the output you are after, however if you use it at a command like, it will give you more examples.
    For a computer it would be dsquery computer -name "Computername"

    For a list of what services are available on which ports, try "IANA assigned ports"

    does this help at all ? If not - please let me know and keep asking, and i'll try and assist
    Please do show your appreciation to those who assist you by leaving Rep Point


    • #3
      Re: Basic Questions

      Hey TehCamel,

      Thanks for the reply. Dsquery answers my first question this is what I was looking for. However for the second question you explained well what TCP/UDP DNS do I want to know for all the ports like what TCP 21 does and UDP 21 does and all. Any link or artcle something where in all the services are explained and the differences between tcp/udp.



      • #4
        Re: Basic Questions

        If you search for IANA Assigned ports, you will be able to find a list of what ports are generally reserved for which well known services.
        Also try IANA well known services.

        In terms of the differnces between tcp and udp, one is connection-oriented, and one isn't. You should be able to find plenty of info on this on the internet already, however if you're having trouble I can find you some links
        Please do show your appreciation to those who assist you by leaving Rep Point


        • #5
          Re: Basic Questions

          Buddy, you're not getting my point -- like you explained difference between tcp and udp services for DNS specifically -- this is what I want to know for all the services.

          links for basic difference between TCP and UDP are there ..... but i would like some links where the difference between tcp/udp for specific services are explained like you explained for DNS.


          • #6
            Re: Basic Questions

            Sorry -- you want us to list every possible port and explain what services use it and how it works?
            Please refer to a little known tool called and do some of your own research
            Tom Jones
            MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
            PhD, MSc, FIAP, MIITT
            IT Trainer / Consultant
            Ossian Ltd

            ** Remember to give credit where credit is due and leave reputation points where appropriate **