Help sharing a dial-up modem with two Ubuntu 6.10 computers - Networking

This is a discussion on Help sharing a dial-up modem with two Ubuntu 6.10 computers - Networking ; So close and yet so far... I have two computers running Ubuntu 6.10 (Edgy Eft) at home. One has an external dial-up modem to connect to the internet, which works great (but obviously slow). We'll call this Computer A. The ...

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Thread: Help sharing a dial-up modem with two Ubuntu 6.10 computers

  1. Help sharing a dial-up modem with two Ubuntu 6.10 computers

    So close and yet so far...
    I have two computers running Ubuntu 6.10 (Edgy Eft) at home. One has
    an external dial-up modem to connect to the internet, which works
    great (but obviously slow). We'll call this Computer A. The other one
    has only a networking card, and we'll call it Computer B. Last night I
    got the two computers to recognize each other over the network and
    share files using (I think) a Samba share. I'm trying to get Computer
    B to be able to access the internet when Computer A is dialed in.

    I followed the instructions on the Firestarter website
    http://www.fs-security.com/docs/connection-sharing.php but took the
    path of static IPs instead of mucking around with a DHCP server.
    _Almost_ everything works. I'm using IPs of 192.168.0.1 for Computer A
    and 192.168.0.2 for Computer B. I can ping each one from the other and
    get a response. As mentioned above, Computer B was able to copy files
    from a shared folder on Computer A. So for the most part, networking
    works. In the Firestarter preferences panel I have the "Internet
    connected network device" set to the modem (PPP0) and the "Local
    network connected device" set to the networking card (ETH0). Internet
    connection sharing is checked, and the DHCP is diabled (not checked).

    Now, here's the question: what do I need to do on Computer B to let
    programs such as Firefox, Synaptic, etc. see the big bad intarweb-
    hicky? They just sort of sit there twiddling their thumbs and saying
    no connection found. The more detailed the instructions, the better.
    Screenshots are good. I spent all night hunting the web for answers
    and they were all hand-wavy and vague.

    -Will


  2. Re: Help sharing a dial-up modem with two Ubuntu 6.10 computers

    larkmore@aol.com wrote:
    > So close and yet so far...
    > I have two computers running Ubuntu 6.10 (Edgy Eft) at home. One has
    > an external dial-up modem to connect to the internet, which works
    > great (but obviously slow). We'll call this Computer A. The other one
    > has only a networking card, and we'll call it Computer B. Last night I
    > got the two computers to recognize each other over the network and
    > share files using (I think) a Samba share. I'm trying to get Computer
    > B to be able to access the internet when Computer A is dialed in.
    >
    > I followed the instructions on the Firestarter website
    > http://www.fs-security.com/docs/connection-sharing.php but took the
    > path of static IPs instead of mucking around with a DHCP server.
    > _Almost_ everything works. I'm using IPs of 192.168.0.1 for Computer A
    > and 192.168.0.2 for Computer B. I can ping each one from the other and
    > get a response. As mentioned above, Computer B was able to copy files
    > from a shared folder on Computer A. So for the most part, networking
    > works. In the Firestarter preferences panel I have the "Internet
    > connected network device" set to the modem (PPP0) and the "Local
    > network connected device" set to the networking card (ETH0). Internet
    > connection sharing is checked, and the DHCP is diabled (not checked).
    >
    > Now, here's the question: what do I need to do on Computer B to let
    > programs such as Firefox, Synaptic, etc. see the big bad intarweb-
    > hicky? They just sort of sit there twiddling their thumbs and saying
    > no connection found. The more detailed the instructions, the better.
    > Screenshots are good. I spent all night hunting the web for answers
    > and they were all hand-wavy and vague.
    >
    > -Will
    >

    Computer B needs to be set up to use Computer A as a gateway (to the
    rest of the world). I don't know about firestarter, but Computer B's
    /etc/network/interfaces file should look like:

    auto eth0
    iface eth0
    address 192.168.0.2
    netmask 255.255.255.0
    gateway 192.168.0.1

    and its /etc/resolv.conf file should contain the same as Computer A's.

    Computer A should have a similar description of eth0 (with different
    address and without the gateway line. It should also be configured to do
    network address translation for Computer B. (the package ipmasq does it
    well for be but I'm sure that there must be better ways by now).

    Robert

  3. Re: Help sharing a dial-up modem with two Ubuntu 6.10 computers

    > larkmore@aol.com wrote:
    >> [Using Computer A as gateway for Computer B]
    >> Now, here's the question: what do I need to do on Computer B to let
    >> programs such as Firefox, Synaptic, etc. see the big bad intarweb-
    >> hicky?


    Robert Harris covered most of the things you need to do.

    In addition, Computer A needs to have IP forwarding turned on. If

    $ cat /proc/sys/net/ipv4/ip_forward

    returns 0, arrange for /etc/sysctl.conf to contain the line

    net.ipv4.ip_forward = 1

    Disclaimer: If Ubuntu puts this configuration information in some other
    place, I'm sure someone will post a correction...

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