Subnetting (Moved to Prevent Thread Hijacking)

Discussion in 'Networking and Internet' started by Zeus, Apr 19, 2006.

  1. Zeus

    Zeus Moderator

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    Not neccessarily true. As long as both computers are set to 255.255.0.0 then they should still be able to see each other.

    For my internal IPs, I use 10.100.X.X for my desktops, 10.150.X.X for my laptops, and 10.255.X.X for my lab.

    Everything can see each other, and my subnet mask is 255.0.0.0. This way if someone does break into my network, they will have to scan the entire Class A to find all of my computers.
     
    Zeus, Apr 19, 2006
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  2. Zeus

    TSEngineer Numenorian

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    Zeus, the reason your setup works is you are using a default subnet mask for your entire network and lab. The default 255.0.0.0 does not subnet your network which is also the reason why a hacker would have to check all 4 million plus combinations. Nick is using a Class C configuration. When using a Class C, you can't use the Class B default subnet (unless you are supernetting). By using 255.255.0.0 the third octet is not defined in the mask for the Class C network, therefore he can't ping (assuming the crossover cable is good or the straight through cable and switch/hub is working correctly). Nick, how are you making out?
     
    Last edited: Apr 20, 2006
    TSEngineer, Apr 20, 2006
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  3. Zeus

    Zeus Moderator

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    TSEngineer, I have a question for you. I always assumed that for a class c network you can use a class b or class a subnet mask and the computers would still see each other. I have never had a total grasp on subnetting so I played with some configurations a bit. I just went in to my entire network and changed everything to 192.168.1.X with a subnet mask of 255.255.0.0 and everything could still see each other, even after the mass reboot. Then I changed everything back to my 10.100.X.X, 10.150.X.X, and 10.255.X.X also using the 255.255.0.0 and everything could still see each other after another reboot. I've put everything back to normal, but why did my computers communicate with each other using the class b subnet mask?
     
    Zeus, Apr 20, 2006
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  4. Zeus

    James Photojournalist

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    What are you using to route? A plain Jane router, some sort of Linux / W2k Server DHCP? You may have setup some sort of relay agent.
     
    James, Apr 20, 2006
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  5. Zeus

    Zeus Moderator

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    Nope not relay agent and I don't use DHCP. I had only my premise router, and everything else was plugged into hubs that were plugged in to the router itself (this way I have more ports for my router).

    Anyway, I posted my last post in a hurry to get out the door. I had to go to work real quick. While there I asked one of our networking guru's and he confirmed what I'm trying to say so I think we just have an overall mis-communication, so here is what I am trying to say broken down.

    You can use 255.255.255.0 for a class c network.
    You can NOT use 255.255.255.0 for a class b or class a network.

    You can use 255.255.0.0 for a class b or class c network.
    You can NOT use 255.255.0.0 for a class a network.

    You can use 255.0.0.0 fror class a, class b or class c networks.
     
    Zeus, Apr 21, 2006
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  6. Zeus

    S Walch MAME 0.64 :) VIP Member

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    If you could explain the difference between the "class networks" - it sounds very complicated to me :S
     
    S Walch, Apr 21, 2006
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  7. Zeus

    spike228 ST 38 VIP Member

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    wow its like cisco all over again, except i don't remember anything haha. i have a vague memory of this stuff but i don't know them exactly.
     
    spike228, Apr 21, 2006
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  8. Zeus

    Dave601 Web Guru VIP Member

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    Yeah, someone explained the classes to me once, but I really don't remember any more. I am pretty sure there is some math in there somewhere, though.
     
    Dave601, Apr 21, 2006
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  9. Zeus

    TheOneGreatX VIP Member

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    TheOneGreatX, Apr 21, 2006
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  10. Zeus

    Goober THQ's Jester Moderator

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    So for class a you could have 192.250.250.4 for on computer and the other one have 192.230.4.250?

    As compared to class c being 192.168.3.4 and 192.168.3.60 ?

    It just allows a greater range of ips right?
     
    Goober, Apr 21, 2006
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  11. Zeus

    Zeus Moderator

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    Yeah, pretty much.
     
    Zeus, Apr 21, 2006
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  12. Zeus

    Goober THQ's Jester Moderator

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    Seems like you left something out...
     
    Goober, Apr 21, 2006
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  13. Zeus

    Zeus Moderator

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    OK, just for you goober...


    yeah, pretty much ;)
     
    Zeus, Apr 21, 2006
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  14. Zeus

    Goober THQ's Jester Moderator

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    Ok I am just gunna go with the flow, and say,


    "Alright, sounds good to me!"
     
    Goober, Apr 21, 2006
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  15. Zeus

    James Photojournalist

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    IIRC, Class A (if we're talking internal) you can only use 10.x.x.x? Isn't that what the point of this thread is?
     
    James, Apr 21, 2006
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