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Thread: routers??

  1. #11
    Some Assembly Required ShagDevil's Avatar
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    It works exactly the same on Freebsd, Linux, windows, whatever
    I bet people who work with multi-vendor networks know that. One small mental note, I only work with Windows platforms.

    I have never ever seen network equipment that's only manageable if you use a certain OS
    That's not really the point here. There's some pretty nice third-party switch management software that I've seen that may not run the same (or run at all) on hosting servers with different OS's (like OpManager). This is something that may be important to consider in a mixed-vendor environment depending on what you're looking for.

    The great thing about TCP/IP is... is it's OS independent
    No way!
    The object of war is not to die for your country but to make the other bastard die for his - George Patton

  2. #12
    Just Another Geek
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    Quote Originally Posted by ShagDevil
    No way!
    Way
    Oliver's Law:
    Experience is something you don't get until just after you need it.

  3. #13
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    There is a lot of good information on the Security Now podcast. Episode 3 and 42 explains a lot about NATs and how they work ( http://www.twit.tv/sn3 http://www.twit.tv/sn42 ). There are also many other basics in the early podcasts that can help you understand how different networking protocols work. Here is the episode guide complete with transcripts: http://www.grc.com/SecurityNow.htm . It's really easy to follow and I learned a lot myself from these podcasts.
    sandwich.

  4. #14
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    also, another thing that i was wondering about was; can a network switch be connected to another network switch?

    i would imagine that there are 2 possibilities. either a switch expects each of its connections to be a specific IP address, and so connecting 2 switches togther would not work. or the two switches would work together, acting as though their is a network bridge between them. i'm expecting that my second assumption is likely to be closer to the truth.


    regards,

    - user0182

  5. #15
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    Quote Originally Posted by user0182
    also, another thing that i was wondering about was; can a network switch be connected to another network switch?
    Yes. Most switches (even the cheap ones) have an "uplink" port. Use that port to "uplink" it to another switch.

    So you get something like this:

    Code:
    [router]-----{uplink}[switch1]{P1}-------{uplink}[switch2]---<PCs>
                                 \{P2}-------{uplink}[switch3]---<PCs>
    Oliver's Law:
    Experience is something you don't get until just after you need it.

  6. #16
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    why is there a distinction between the "uplink" port and the other ports? i guess that there may be a reason to use an "uplink" port to connect to a router, although i still don't fully understand.

    if i understand correctly; a switch is just a series of network bridges, and in principle is the same as placing a bridge between each of the machines that you have attached to the switch.

    therefore, as a bridge learns which IP addresses that are on either side of it's interfaces, shouldn't any switch be able to learn a group of IP addresses for each of it's interfaces?

    thus, wouldn't the following work?:

    Code:
    [router]----(uplink)[switch](p1)----(p1)[switch2](p2-p4)----<PCs>
                               /(p2)----(p1)[switch3](p2-p4)----<PCs>
    although, i still don't really understand why the following would not work?:

    Code:
    [router]----(p1)[switch1](p2)----(p1)[switch]----<PCs>
                            /(p3)----(p1)[switch]----<PCs>

    regards,

    - user0182
    Last edited by user0182; July 25th, 2008 at 01:41 PM.

  7. #17
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    Quote Originally Posted by user0182
    why is there a distinction between the "uplink" port and the other ports?
    The RxD and TxD are reversed.
    Having said that, a lot of modern switches/networkcards are auto-sensing and switch automatically from "normal" to "uplink" (i.e. reversing TxD/RxD).
    With the more expensive equipment the "uplink" port is usually also faster. So for instance you'll have 24 10/100Mbit switched ports and 2 1Gbit uplinks.

    Without this automatic changing, if you need to connect:

    [router]-----{uplink}[switch] (straight cable)
    [switch]{p1}----[PC] (straight cable)
    [switch]{p1}----{uplink}[switch2] (straight cable)
    [switch]{p1}--X--{p1}[switch2] (cross-cable)
    [PC]--X--[PC] (cross-cable)
    [router]--X--[router] (cross-cable)

    therefore, as a bridge learns which IP addresses {...}
    A bridge works on layer 2, IP is layer 3.
    Last edited by SirDice; July 25th, 2008 at 02:44 PM.
    Oliver's Law:
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  8. #18
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    what is RxD and TxD?

    what i meant by a bridge learns IP addresses, is it learns MAC addresses but as each MAC address maps to an IP address, therefore it sort of learns IP addresses.

  9. #19
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    Quote Originally Posted by user0182
    what is RxD and TxD?
    Receive Data and Transmit Data.. Of the 8 pins in a RJ45, 4 are connected (with 'regular' 10/100Mbit ethernet).
    2 for RxD and 2 for TxD. You connect a Transmit to a Receive and vise versa.

    what i meant by a bridge learns IP addresses, is it learns MAC addresses but as each MAC address maps to an IP address, therefore it sort of learns IP addresses.
    A bridge has no notion of the MAC-IP relationship. Do learn the correct basics or you'll end up not understanding the more complex stuff

    http://en.wikipedia.org/wiki/OSI_model
    Last edited by SirDice; July 25th, 2008 at 04:11 PM.
    Oliver's Law:
    Experience is something you don't get until just after you need it.

  10. #20
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    A bridge has no notion of the MAC-IP relationship. Do learn the correct basics or you'll end up not understanding the more complex stuff
    now i am confused! i know that a standard switch does not look at, nor has any understanding of IP addresses, i just think i may not have been communicating accurately, as most of the time sending to an IP address or a MAC address on a LAN has the same effect. i thought that a switch is a series of bridges, and each bridge learns the MAC addresses that are on either side of itself (i.e. operating at layer 2 of OSI), and thus only transmits packets where the source and destination MAC addresses are on different sides of the bridge. am i correct?

    btw: i really appreciate all of your help SirDice. this is why i wanted to create this thread, as i find this stuff interesting and i wanted to check my knowledge.


    regards,

    - user0182
    Last edited by user0182; July 26th, 2008 at 09:31 PM.

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