Bridging two wired networks via wireless router and NIC

Discussion in 'Wireless Networking' started by Guest, Feb 24, 2006.

  1. Guest

    Guest Guest

    My home network has five computers and two routers:

    Router #1 has the Internet, VoIP Phone, and DHCP Server. It is connected
    directly to the DSL modem and dials out via PPPoE through the ethernet port.

    Router #2 has the 802.11g wireless radio, DHCP disabled, and otherwise acts
    like a dumb ethernet switch connected via ethernet to a LAN port of Router
    #1. IP:

    Computers A, B, and C are connected to Router #2 via ethernet and are
    configured to use the DHCP which works fine.

    The problem is that computers D and E are situated on the other side of the
    house, and only D gets reliable signal reception even with a Linksys SRX
    wireless NIC.

    Computer D has the wireless adapter and an ethernet adapter. Both adapters
    are configured to use DHCP.

    Computer E has an ethernet port (nForce 4) which is configured to use DHCP.

    Now, here's the problem. I want the following:

    E <-> ethernet <-> Bridge on D <-> wireless <-> Router #2...

    From what I have read this should put all computers on the
    subnet with DHCP-assigned addresses from Router #1. But it doesn't work, and
    I can't find any troubleshooting for this on the Internet.

    The bridge on computer D establishes itself, acquires its MAC address and
    DHCP information from the wireless adapter, and reports that everything is
    OK; however, it cannot ping any computers or routers on the wireless side of
    the bridge. Neither Internet access nor network shares work.

    The status windows for the bridge, wired, and wireless connections show that
    packets are being sent and received to varying degrees when I try to ping the
    routers and the other computers. But the pings will timeout and tracert will
    just sit there for what seems like an eternity.

    The computers are running XP SP2, BTW.

    What can I do? Are there any troubleshooting steps I can take to narrow the
    problem down? If this is a Linksys issue, then I want more specific
    information to give them.

    Before you ask:

    The promiscuous mode fix on D's wireless adapter did not change anything.

    Using ICS on D is not acceptable; D and C are PVRs (SageTV) and need to see
    each other and the rest of the home network so that they can share recorded
    shows and live TV feeds.
    Guest, Feb 24, 2006
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  2. Guest

    James Gockel Guest

    Ok, first thing I need to know, is, do you have a crossover cable? between D
    and E?
    That could be the major problem right now.
    Other than that, I'm doing pretty much the same thing right now... using my
    laptop as the wireless "card" bridged to a computer...
    some ways you can over come this is by:
    A) buy another router and connect it that WAN to the wireless computer...
    and all other computers to it... but why not spring for the wireless
    repeater if you're going to do that? ;-) unless you have one lying around
    (like I do)
    B) using a crossover cable to connect the two computers D and E bridging the
    networks on D.

    Then everything should work. ;-) Good luck.
    BTW, promiscuos mode only does stuff for sniffers (or hackers)... nothing
    workable for usage like that... IMO

    -James G.
    James Gockel, Feb 24, 2006
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  3. Guest

    Guest Guest

    Thanks for your quick response, James!

    Why would I need a crossover cable? Using a standard cable, ICS on D seems
    to work fine in lieu of a XP bridge with the exception that neither D nor E
    can see the other computers on the home network.

    In any case, I have a spare switch and a 3' ethernet cable which should take
    the place of a cross-over cable...I'll give this a try tomorrow.
    I'm not sure what you are suggesting, but I have two wired networks which
    cannot be connected without using some form of wireless technology between

    To clarify, there are two locations within the house:

    On one side of the house:
    DSL Modem
    Router #1 (VoIP)
    Router #2 (wireless and ethernet)
    Computer A
    Computer B
    Computer C

    On the other side of the house:
    Computer D
    Computer E

    No cables can bridge the two separate locations. The head of the house says
    so "no" (very emphatically) to running cables between them (although 100 ft.
    CAT-5 would probably do it).

    Also, E cannot get a good wireless signal to the wireless router on the
    other end of the house. The signal would have to travel through the
    entertainment center, the kitchen, and quite a few walls (since we're going
    diagonally). Blame the architect and the cable installer. But really, houses
    should be wired for ethernet...

    For this reason, E must have a wired connection to D, and D must have a
    wireless connection to the rest of the network.

    BTW, I have a spare wireless router and two spare wireless NICs lying around
    in case that opens up some more options.
    I was referring to the promiscuous mode problem in the MS KB which can
    prevent some wireless NICs from working in an XP network bridge.
    Guest, Feb 24, 2006
  4. Guest

    James Gockel Guest

    Just ignore the last part of the message, it was a tangent I went on. I just
    meant that my network sounds similar to your situation. I have it like this

    <E> = Connected by CAT5 Ethernet
    <W> = Connected Wirelessly

    DSL Modem
    ->Wireless Router
    |-> <E> Laptop A
    |-> <E> Printer A
    |-> <W> Computer A (Sharing Printer B)
    |-> <W> Computer B
    |-> <W> Laptop B
    -> <W> Laptop C (mine) (Bridged Wireless and Ethernet)
    | Into wan port, so crossover isnt needed.
    -> <E> Router
    -> <E> Computer C

    If you were to connect, in mycase, Laptop C and Computer C directly you'd
    need a crossover cable.

    I think a crossover cable or a switch should work, in your case. Should be
    simple =)
    -James G.
    James Gockel, Feb 24, 2006
  5. Guest

    Guest Guest

    OK, I understand now. Thanks for the advice!
    Guest, Feb 25, 2006
  6. Guest

    Guest Guest

    Heh, success at last.

    So the following combinations:

    [wireless router] -> [wireless NIC #1 -> (xp bridge) <- ethernet NIC] ->
    [internet router]
    [wireless router] -> [wireless NIC #2 -> (xp bridge) <- ethernet NIC] ->
    [internet router]
    [wireless router] -> [ethernet NIC -> (xp bridge) <- wireless NIC #2] ->
    [internet router]

    do not work. Specifically, the computer with the bridged connection is never
    able to ping both routers successfully. The promiscuous mode fix does not
    help here.

    However, this combination:

    [wireless router] -> [ethernet NIC -> (xp bridge) <- wireless NIC #1] ->
    [internet router]

    does work if I toggle the forcecompatmode option with the proper timing. Cool!

    But then it fails after a day or so. I have the XP bridge set to a static
    IP, so it's not a DHCP lease issue. The wireless NIC #1 just loses its
    ability to communicate with the wireless router, and toggling the
    forcecompatmode seems like the only way to fix it. DNS lookups are slow as
    heck right now - we're talking > 5 seconds.

    Hey, look at that!!! I tried to ping my ISP's name servers from behind the
    bridge about five minutes ago with an infinite timeout period, and the first
    ping just succeeded. Yay. Now I wonder why I get DNS lookups faster than I
    can ping the DNS servers. Perhaps the connection times out and then pulls
    values from a cache.

    I will start an email discussion Linksys to resolve these problems. Most
    likely there are simply bugs in the wireless router and wireless NICs'
    firmware that need to be pointed out and fixed.

    For future reference, my Linksys hardware is as follows:

    RT31P2 (works fine with the bridge)
    WRT54G (works fine on the non-Internet side of the bridge)
    WUSB54G (works fine on the Internet side of the bridge)
    WMP54GX (doesn't work with the bridge on either side)

    (Cross your fingers!)
    Guest, Feb 25, 2006
  7. Guest

    Guest Guest

    Linksys says that only ad-hoc and infrastructure modes are supported on
    their wireless NICs; instead of fixing the driver bugs, however, they offered
    to let me buy a hardware bridge. Gee, how nice of them. And do you know how
    many bridges Linksys sells with SRX technology? Zero. Looks like eBay will be
    getting some more business soon...
    Guest, Feb 27, 2006
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