Whats with DNS servers?
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Thread: Whats with DNS servers?

  1. #1
    Senior Member br_fusion's Avatar
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    Whats with DNS servers?

    I need a littel help with DNS(Domain Name System).

    Ive read alot about DNS, and that it is a server/program that converts IP's to address's like(www.google.com) however i don't really understand them.

    For instance, a LAN running on T1, I run a "ipconfig /all" to see the IP/Gateway/NIC addresses. In this information I also see two IPS assigned to DNS. What does this mean exactly? And also when I ping the IP's from the LAN, i get no response.

  2. #2
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    I'm a little confused here.

    "The Domain Name System (DNS) is a distributed Internet directory service. DNS is used mostly to translate between domain names and IP addresses, and to control Internet email delivery. Most Internet services rely on DNS to work, and if DNS fails, web sites cannot be located and email delivery stalls." - http://www.dns.net/dnsrd/

    You can visit that site to find out more information. God bless google.


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  3. #3
    Senior Member br_fusion's Avatar
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    well my facts were off.

    But why would their be DNS servers running on a LAN?

  4. #4
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    DNS servers running on a LAN? I find that very likely. DNS servers serve multiple IP addresses, and are often used in domain (.com, .org, .net, etc.) management, and are almost always very busy. The reason why its likely is because you'd normally think they'd be more than one server, right? Well, what better way than connect the servers through a LAN?


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    Silentstalker
    -{[ Joe ]}- (Joe@nitesecurity.com)
    http://www.nitesecurity.com

    [shadow]I\'m Just A Soldier In This War Against Ignorance.[/shadow]

  5. #5
    AO übergeek phishphreek's Avatar
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    You would want DNS servers on a LAN/WAN so you can resolve computer names to ip addresses much easier than constantly editing your hosts file on every PC any time there is a change in the network.

    If you use DHCP, and you want to find a computer named "bob", you'd need DNS.
    Today bob's address was different than yesterday, and you don't want to search for bob individually trying differnt ip addresses. Thats where DNS comes in. The DNS will know bob's address and connect you that way.

    There is much much more involved than that. That is just an example.

    EDIT: Silentstalker, you are correct. Some people use them for that, but a proxy would be more useful for that.
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  6. #6
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    Ok, to answer your question of "why would their DNS servers be running on a LAN," I can tell you that DNS is very much a part of Windows 2000 Active Directory. It relies on DNS for it's infrastructure. In a way - for Windows - it has replaced WINS (Windows Internet Naming Service) servers. Their job was to map NetBIOS names - used in UNC (Universal Naming Convention) paths like \\server1\share1 - to IP addresses so that there was less broadcast traffic on the network. Basically, without a WINS server (in the past), your machine would have to send out a broadcast along the lines of: whoever has the Netbios name of server1, please send me your IP address so that we can communicate. Now, what WINS did was this: for every Windows machine that was configured as a WINS client, it would register with the WINS server its Netbios name, corresponding IP address, and MAC address so that this broadcast traffic could be eliminated. Nowadays, the only reason people have WINS servers is for Win9x clients since they are not as much integrated into the AD structure. However, the Directory Service client can be installed for them to be able to search AD. As far as DNS goes in AD, it can be used for the clients to register their hostnames with the corresponding IP and MAC address as well as accessing external network hostnames in the same manner. Somehow, DNS is more efficient at the mapping for the local network also, so I've been told. I hope that helps a bit more. You may want to check out the link presented above for more information. Anyone that finds my information incomplete or inaccurate, please feel free to correct me intelligently . It's been a little while since I have studied networking.


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  7. #7
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    DNS Servers

    Well, I manage 10 DNS servers
    7 I own
    6 are on internal LANS
    4 are public DNS's
    I use Both Linux and Windows Base DNS's

    Think of a DNS server like a Phone Book

    But if you want more info, try the links below

    news://news.grc.com

    http://ntcanuck.com/

    I hope this helps.
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    And learning to Play the Bugle

  8. #8
    Antionline's Security Dude instronics's Avatar
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    Why run a DNS on a LAN?

    Uhm.....imagine you have 30 - 50 computers in a company. Could you remember each ip number of every computer? That might be difficult. I get confused with our company LAN which only has 12 computers. I control them via hostnames instead of ip numbers. Much easier and since we do have the resources of setting up a DNS server, heck why not?
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  9. #9
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    Red face DNS

    Using Bind_PE you can have both... A desktop computer
    and a DNS server....

    Another thing, that DNS software is FREE!!!
    No GUI but if you use Linux Bind 9, it sets up
    just like Linux on a Windows Box...

    With internal DNS servers you can if needed block
    sites via names... think of the problem with whitehouse.gov and com
    it is an easy example....
    Another is blocking the use of IM programs for security reasons.
    I have on my personal LAN 7-10 computers running at one time...
    and I have 3 DNS servers... (I like to play)

    One customer I have with 20 computers I use Bind_PE as a
    secondary DNS and their Cobalt Raq 4 webserver as primary

    Another customer I use Bind_PE as primary and the DNS's
    available at the ISP's as secondary... used only if the
    Internal DNS dies....
    Franklin Werren at www.bagpipes.net
    Yes I do play the Bagpipes!

    And learning to Play the Bugle

  10. #10
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    Re: Whats with DNS servers?

    Originally posted here by br_fusion
    For instance, a LAN running on T1, I run a "ipconfig /all" to see the IP/Gateway/NIC addresses. In this information I also see two IPS assigned to DNS. What does this mean exactly? And also when I ping the IP's from the LAN, i get no response.
    hi

    i'm not sure if you got an answer for this bit. the firewall could be set to silently drop your pings, so it doesn't get spammed/dos'd by ping's icmp packets.

    regards,
    mark.
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