IP Address Assignment
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Thread: IP Address Assignment

  1. #1
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    IP Address Assignment

    Good Evening:

    I'm not sure how to explain this, but I'll try.

    Say a PC on a LAN is turned ON, and in the TCP/IP properties it says to obtain an IP address from the DHCP server. How does the PC know what machine on the network is the DHCP server and how is the request send from the PC?

    Thankyou.

  2. #2
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    Hey Hey,

    Check out this tutorial... http://www.antionline.com/showthread...hreadid=258242

    It had mixed reviews, but it'll definately explain the basics behind DHCP.

    Peace,
    HT
    IT Blog: .:Computer Defense:.
    PnCHd (Pronounced Pinched): Acronym - Point 'n Click Hacked. As in: "That website was pinched" or "The skiddie pinched my computer because I forgot to patch".

  3. #3
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    Originally posted here by HTRegz
    Hey Hey,

    Check out this tutorial... http://www.antionline.com/showthread...hreadid=258242

    It had mixed reviews, but it'll definately explain the basics behind DHCP.

    Peace,
    HT
    Good Evening

    --To a beginner like myself, *Excellent* Tutorial. This is what exactly I was looking for. My whole-hearted *Thankyou*.

    On a Tangent, How can I emulate Machines on the network, to claim real IP addresses from the DHCP? This is for purely Educational Purposes.

    Thankyou.

  4. #4
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    Originally posted here by FallenZer0
    Good Evening

    --To a beginner like myself, *Excellent* Tutorial. This is what exactly I was looking for. My whole-hearted *Thankyou*.

    On a Tangent, How can I emulate Machines on the network, to claim real IP addresses from the DHCP? This is for purely Educational Purposes.

    Thankyou.
    Hey Hey,

    You'll need two things...... A Sniffer, and some sort of injection/packet building tool.

    Two or three computers and a hub are all that you need.

    Set up the PCs.... I'll discuss as if you were using two (or two virtual machines even)... If you have three.. then the sniffer and DHCP would be independent...

    Setup a DHCP Server plugged into your hub.. Start up a sniffer on this machine...

    Boot your other machine and watch the packet captures... you'll see all the packets from the DHCP process. Now use your packet injection/building tool and form a packet similar to the one your PC originally sent out.. Watch your sniffer for a response... and then using that data and what you know about DHCP packets (from your first sniff) respond to it... Continue this process until all the steps are completed... Then go to your DHCP server and check out the leases.

    This should get you through it for Educational purposes.... if you have any more questions let me know.

    Peace,
    HT
    IT Blog: .:Computer Defense:.
    PnCHd (Pronounced Pinched): Acronym - Point 'n Click Hacked. As in: "That website was pinched" or "The skiddie pinched my computer because I forgot to patch".

  5. #5
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    Good Morning HTRegz:

    Thankyou for sharing your Knowledge.

    Unfortunately, I've only one PC which is W2K Professional and Ethereal Packet Analyzer. If I buy an inexpensive Router, do you think I can use it as a DHCP server? Even if I buy one, do I need to have a 2nd PC as per your example?

    Thankyou For Your Guidance & Have A Great Day.

  6. #6
    Just a Virtualized Geek MrLinus's Avatar
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    If I buy an inexpensive Router, do you think I can use it as a DHCP server?
    Yes, most likely. I have some NetGear Routers and Switches designed for home/SOHO use and they have built in DHCP servers.

    Even if I buy one, do I need to have a 2nd PC as per your example
    It'd be ideal to have a 2nd machine so one machine becomes the "attacker" while the other is the observer. But you could probably do this with one machine and the DHCP server on the Router.
    Goodbye, Mittens (1992-2008). My pillow will be cold without your purring beside my head
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  7. #7
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    Originally posted here by MsMittens
    Yes, most likely. I have some NetGear Routers and Switches designed for home/SOHO use and they have built in DHCP servers.

    Good Morning:

    Would you mind to let me know what the NetGear Router/Switch would cost me to purchase it from you? I'm sorry if I misunderstood you.

    Thankyou.

  8. #8
    Just a Virtualized Geek MrLinus's Avatar
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    Would you mind to let me know what the NetGear Router/Switch would cost me to purchase it from you?
    LOL. I don't sell them. When I say I have some, it means I use them. Amazon sells them for about $40USD. You might be able to get it cheaper at your local computer shop.
    Goodbye, Mittens (1992-2008). My pillow will be cold without your purring beside my head
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