Noob Routing Table Question - Network

This is a discussion on Noob Routing Table Question - Network ; I hope the columns line up... Active Routes: Network Destination Netmask Gateway Interface 0.0.0.0 0.0.0.0 68.82.196.1 68.82.196.102 68.82.196.0 255.255.255.0 68.82.196.102 68.82.196.102 68.82.196.102 255.255.255.255 127.0.0.1 127.0.0.1 68.255.255.255 255.255.255.255 68.82.196.102 68.82.196.102 127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 224.0.0.0 240.0.0.0 68.82.196.102 68.82.196.102 255.255.255.255 255.255.255.255 68.82.196.102 ...

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Thread: Noob Routing Table Question

  1. Noob Routing Table Question

    I hope the columns line up...

    Active Routes:
    Network Destination Netmask Gateway Interface
    0.0.0.0 0.0.0.0 68.82.196.1 68.82.196.102
    68.82.196.0 255.255.255.0 68.82.196.102 68.82.196.102
    68.82.196.102 255.255.255.255 127.0.0.1 127.0.0.1
    68.255.255.255 255.255.255.255 68.82.196.102 68.82.196.102
    127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1
    224.0.0.0 240.0.0.0 68.82.196.102 68.82.196.102
    255.255.255.255 255.255.255.255 68.82.196.102 68.82.196.102
    Default Gateway: 68.82.196.1
    ================================================== =========================

    Question: I have a single computer, accessing the internet via cable modem.
    Say an app on my computer (68.82.196.102) wants to send a packet to
    68.82.196.105 (some other cable modem user in my city). Using the above
    routing table (the result of a route print command), how does the packet get
    anywhere? Seems to me the most specific match will be on the second entry
    (68.82.196 subnet), which will route to gateway 68.82.196.102 (my IP) via
    interface 68.82.196.102 (my IP). So how the heck does the packet get 'out'?
    TIA.
    ---Mick




  2. Re: Noob Routing Table Question

    Your routing table only knows the routes it has learned up TO your
    gateway. From your gatway what ever is in IT's routing table depends
    how the packet will travel.

    If you do a Traceroute (tracert) in windows you will see every router
    it passes to get to it's destination. You'll see that each router has
    information of it's neigboring routers.

  3. Re: Noob Routing Table Question

    Mauricio, thanks. I understand what you're saying, but the question was
    (stated a slightly different way)...
    How does my computer know to send a packet for 68.82.196.105 to the gateway
    (68.82.196.1)? Why doesn't it get 'stuck' on the second entry below? Which
    entry below gets it to 68.82.196.1... the first entry? Wouldn't the second
    entry (more specific, longer mask) keep the packet at my computer? TIA.
    ---Mick


    Active Routes:
    Network Destination Netmask Gateway Interface
    0.0.0.0 0.0.0.0 68.82.196.1 68.82.196.102
    68.82.196.0 255.255.255.0 68.82.196.102 68.82.196.102
    68.82.196.102 255.255.255.255 127.0.0.1 127.0.0.1
    68.255.255.255 255.255.255.255 68.82.196.102 68.82.196.102
    127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1
    224.0.0.0 240.0.0.0 68.82.196.102 68.82.196.102
    255.255.255.255 255.255.255.255 68.82.196.102 68.82.196.102
    Default Gateway: 68.82.196.1


    "Mauricio Fernandez MCSE, CCNA" wrote in message
    news:90ebab91.0405030455.30492a5c@posting.google.c om...
    > Your routing table only knows the routes it has learned up TO your
    > gateway. From your gatway what ever is in IT's routing table depends
    > how the packet will travel.
    >
    > If you do a Traceroute (tracert) in windows you will see every router
    > it passes to get to it's destination. You'll see that each router has
    > information of it's neigboring routers.




  4. Re: Noob Routing Table Question

    If you'd be sending a packet to the IP Specified it would never reach
    your gateway because it is in the "SAME NETWORK".

  5. Re: Noob Routing Table Question

    Okay, but couldn't there be another cable modem user in my city with that IP
    address (maybe he's running a little web server or something), and how could
    I ever ping him if I can't get to the gateway because it's the 'same
    network'? TIA.
    ---Mick

    "Mauricio Fernandez MCSE, CCNA" wrote in message
    news:90ebab91.0405051714.8e8b676@posting.google.co m...
    > If you'd be sending a packet to the IP Specified it would never reach
    > your gateway because it is in the "SAME NETWORK".




  6. Re: Noob Routing Table Question

    "Mick" wrote in message news:...
    > I hope the columns line up...
    >
    > Active Routes:
    > Network Destination Netmask Gateway Interface
    > 0.0.0.0 0.0.0.0 68.82.196.1 68.82.196.102
    > 68.82.196.0 255.255.255.0 68.82.196.102 68.82.196.102
    > 68.82.196.102 255.255.255.255 127.0.0.1 127.0.0.1
    > 68.255.255.255 255.255.255.255 68.82.196.102 68.82.196.102
    > 127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1
    > 224.0.0.0 240.0.0.0 68.82.196.102 68.82.196.102
    > 255.255.255.255 255.255.255.255 68.82.196.102 68.82.196.102
    > Default Gateway: 68.82.196.1
    > ================================================== =========================
    >
    > Question: I have a single computer, accessing the internet via cable modem.
    > Say an app on my computer (68.82.196.102) wants to send a packet to
    > 68.82.196.105 (some other cable modem user in my city). Using the above
    > routing table (the result of a route print command), how does the packet get
    > anywhere?


    **** Interface = YOUR IP machine like you said.
    **** The IP listed to the left of your Interface "IS" your gateway.
    **** That gateway is the machine that fowards your packets out to the
    real world. The "GATEWAY" is probably a router with it's OWN routing
    table.
    Depending on the Routing protocol (probably BGP) the gateway decides
    where your pacet travels from there. It repeats the step till it gets
    to it's destination.



    Seems to me the most specific match will be on the second entry
    > (68.82.196 subnet), which will route to gateway 68.82.196.102 (my IP) via
    > interface 68.82.196.102 (my IP). So how the heck does the packet get 'out'?
    > TIA.
    > ---Mick


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