Bridging Wireless and Ethernet subnets

Discussion in 'Wireless Networking' started by Eddy Borg, Oct 25, 2004.

  1. Eddy Borg

    Eddy Borg Guest

    I have a small LAN made of two desktops with Ethernet
    adapters, linked with a cross cable (no hubs, no routers),
    which is working fine.
    In order to add to the network a laptop (Centrino WinXP
    SP1 with a preinstalled Intel PRO/Wireless LAN 2100 3B
    Mini PCI Adapter 811.b), I bought a Qtec Wireless adapter
    802.11g, installed it on one of the desktops (WinXP SP1),
    and configured it as an ad-hoc subnet (with no security to
    start with).
    The WiFi subnet is working (laptop-desktop1), but
    obviously cannot see the Ethernet subnet (desktop1-
    desktop2) and viceversa.
    In more detail: If I use two different ranges (192.168.0.x
    and 169.254.x.y) they coexist separately, whereas if I use
    the same range (169.254.x.y) they conflict because they
    are based on different media (Ethernet-WiFi).
    I therefore started to set up a Windows XP Bridge which is
    supposed to just merge the two subnets into one, but I
    could'nt make it work. The two WiFi cards don't see each
    other across the bridge!
    Although I read a lot of documentation from various
    sources I could'nt find a solution todate.
    Amongst other things I did:
    1. Force promiscuity mode, as some adapters are not able
    to enter that mode automatically when in the bridge
    (source Microsoft)
    2. Update driver to the Qtec adapter, as the 802.11g
    standard was finally defined after many adapters were
    already on the market, and interoperability could not be
    guaranteed (source Internet, somewhere)
    3. Setup a bridge also on the laptop in case the two WiFi
    cards can communicate only if they are both in 'bridge
    mode' (I'm not sure).
    Can somebody help, please?
    Eddy
    Eddy Borg, Oct 25, 2004
    #1
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  2. Eddy Borg

    Jack Guest

    Hi

    First keep in mind that there is No WIFI vs. Ethernet.

    It is all Ethernet. Wireless is just a replacement to a Wire and the name
    WIFI is the name of the device certification.

    If your Wireless works by it self I.e. you can really transfer files via
    wireless between the computers (not just see signal in the utility) you
    should be able to bridge Since you mentioned the 169.x.x. I have the feeling
    that something is not working right and thus you can not Bridge.

    The two networks as to be configured along the line of (Example) Wired
    Network 192.168.1.1 and Wireless Network 192.168.2.1 or similar ranges.

    Jack (MVP-Networking).







    "Eddy Borg" <> wrote in message
    news:0c1701c4ba97$a32b2bc0$...
    > I have a small LAN made of two desktops with Ethernet
    > adapters, linked with a cross cable (no hubs, no routers),
    > which is working fine.
    > In order to add to the network a laptop (Centrino WinXP
    > SP1 with a preinstalled Intel PRO/Wireless LAN 2100 3B
    > Mini PCI Adapter 811.b), I bought a Qtec Wireless adapter
    > 802.11g, installed it on one of the desktops (WinXP SP1),
    > and configured it as an ad-hoc subnet (with no security to
    > start with).
    > The WiFi subnet is working (laptop-desktop1), but
    > obviously cannot see the Ethernet subnet (desktop1-
    > desktop2) and viceversa.
    > In more detail: If I use two different ranges (192.168.0.x
    > and 169.254.x.y) they coexist separately, whereas if I use
    > the same range (169.254.x.y) they conflict because they
    > are based on different media (Ethernet-WiFi).
    > I therefore started to set up a Windows XP Bridge which is
    > supposed to just merge the two subnets into one, but I
    > could'nt make it work. The two WiFi cards don't see each
    > other across the bridge!
    > Although I read a lot of documentation from various
    > sources I could'nt find a solution todate.
    > Amongst other things I did:
    > 1. Force promiscuity mode, as some adapters are not able
    > to enter that mode automatically when in the bridge
    > (source Microsoft)
    > 2. Update driver to the Qtec adapter, as the 802.11g
    > standard was finally defined after many adapters were
    > already on the market, and interoperability could not be
    > guaranteed (source Internet, somewhere)
    > 3. Setup a bridge also on the laptop in case the two WiFi
    > cards can communicate only if they are both in 'bridge
    > mode' (I'm not sure).
    > Can somebody help, please?
    > Eddy
    Jack, Oct 26, 2004
    #2
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  3. Eddy Borg

    Pavel A. Guest

    Most wi-fi adapters do NOT support ethernet style bridging,
    because they can not work in true promiscuous mode.
    And this is because they only simulate ethernet, but really are
    not ethernet (despite of beliefs of some MVPs).
    Either enable routing, or use NAT.

    There are 802.11 devices specially designed to work as
    ethernet bridges, but most cheapo wi-fi's, by design, are not.

    Regards,
    --PA



    "Eddy Borg" <> wrote in message news:0c1701c4ba97$a32b2bc0$...
    > I have a small LAN made of two desktops with Ethernet
    > adapters, linked with a cross cable (no hubs, no routers),
    > which is working fine.
    > In order to add to the network a laptop (Centrino WinXP
    > SP1 with a preinstalled Intel PRO/Wireless LAN 2100 3B
    > Mini PCI Adapter 811.b), I bought a Qtec Wireless adapter
    > 802.11g, installed it on one of the desktops (WinXP SP1),
    > and configured it as an ad-hoc subnet (with no security to
    > start with).
    > The WiFi subnet is working (laptop-desktop1), but
    > obviously cannot see the Ethernet subnet (desktop1-
    > desktop2) and viceversa.
    > In more detail: If I use two different ranges (192.168.0.x
    > and 169.254.x.y) they coexist separately, whereas if I use
    > the same range (169.254.x.y) they conflict because they
    > are based on different media (Ethernet-WiFi).
    > I therefore started to set up a Windows XP Bridge which is
    > supposed to just merge the two subnets into one, but I
    > could'nt make it work. The two WiFi cards don't see each
    > other across the bridge!
    > Although I read a lot of documentation from various
    > sources I could'nt find a solution todate.
    > Amongst other things I did:
    > 1. Force promiscuity mode, as some adapters are not able
    > to enter that mode automatically when in the bridge
    > (source Microsoft)
    > 2. Update driver to the Qtec adapter, as the 802.11g
    > standard was finally defined after many adapters were
    > already on the market, and interoperability could not be
    > guaranteed (source Internet, somewhere)
    > 3. Setup a bridge also on the laptop in case the two WiFi
    > cards can communicate only if they are both in 'bridge
    > mode' (I'm not sure).
    > Can somebody help, please?
    > Eddy
    Pavel A., Oct 27, 2004
    #3
  4. Sorry for the late follow-up.
    I try and clarify the situation in case I have not been able to make it
    clear in my previous post.
    I have three computers: A (Ethernet adapter and wireless adapter), B
    (Ethernet adapter), and C (wireless adapter). A and B are linked with a cross
    RJ45 cable (no hub). A and C are linked wireless.
    Both subnets work perfectly (they ping each other AND transfer data).
    To link them together I have created a WinXP (software) bridge on A,
    incluthing the two adapters.
    Whereas A and B can communicate through the bridge, A and C cannot (no data,
    no ping).
    MS Knoledge Base states that this might be due to the wireless adapter
    within the bridge not being able to automatically enter promiscuous mode
    (layer2), and that this can be worked around by forcing compatibility mode
    (layer3).
    The above has to be done with the command netsh bridge set a x e (x being
    the number of the adapter).
    I have done that and checked that compatibility mode has been enabled;
    however, A and C still do not communicate under the bridge (they do outside
    the bridge).
    Is there a way to solve this without having to buy a router or configuring A
    to act like a router (I need it for ICS)?
    Is the Qtec 54G wireless adapter not compatible with WinXP bridge?
    Have I done something wrong?
    thanks and regards
    Eddy

    "Jack" wrote:

    > Hi
    >
    > First keep in mind that there is No WIFI vs. Ethernet.
    >
    > It is all Ethernet. Wireless is just a replacement to a Wire and the name
    > WIFI is the name of the device certification.
    >
    > If your Wireless works by it self I.e. you can really transfer files via
    > wireless between the computers (not just see signal in the utility) you
    > should be able to bridge Since you mentioned the 169.x.x. I have the feeling
    > that something is not working right and thus you can not Bridge.
    >
    > The two networks as to be configured along the line of (Example) Wired
    > Network 192.168.1.1 and Wireless Network 192.168.2.1 or similar ranges.
    >
    > Jack (MVP-Networking).
    >
    >
    >
    >
    >
    >
    >
    > "Eddy Borg" <> wrote in message
    > news:0c1701c4ba97$a32b2bc0$...
    > > I have a small LAN made of two desktops with Ethernet
    > > adapters, linked with a cross cable (no hubs, no routers),
    > > which is working fine.
    > > In order to add to the network a laptop (Centrino WinXP
    > > SP1 with a preinstalled Intel PRO/Wireless LAN 2100 3B
    > > Mini PCI Adapter 811.b), I bought a Qtec Wireless adapter
    > > 802.11g, installed it on one of the desktops (WinXP SP1),
    > > and configured it as an ad-hoc subnet (with no security to
    > > start with).
    > > The WiFi subnet is working (laptop-desktop1), but
    > > obviously cannot see the Ethernet subnet (desktop1-
    > > desktop2) and viceversa.
    > > In more detail: If I use two different ranges (192.168.0.x
    > > and 169.254.x.y) they coexist separately, whereas if I use
    > > the same range (169.254.x.y) they conflict because they
    > > are based on different media (Ethernet-WiFi).
    > > I therefore started to set up a Windows XP Bridge which is
    > > supposed to just merge the two subnets into one, but I
    > > could'nt make it work. The two WiFi cards don't see each
    > > other across the bridge!
    > > Although I read a lot of documentation from various
    > > sources I could'nt find a solution todate.
    > > Amongst other things I did:
    > > 1. Force promiscuity mode, as some adapters are not able
    > > to enter that mode automatically when in the bridge
    > > (source Microsoft)
    > > 2. Update driver to the Qtec adapter, as the 802.11g
    > > standard was finally defined after many adapters were
    > > already on the market, and interoperability could not be
    > > guaranteed (source Internet, somewhere)
    > > 3. Setup a bridge also on the laptop in case the two WiFi
    > > cards can communicate only if they are both in 'bridge
    > > mode' (I'm not sure).
    > > Can somebody help, please?
    > > Eddy

    >
    >
    >
    =?Utf-8?B?RWRkeSBCb3Jn?=, Nov 16, 2004
    #4
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