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Wireless/Wired Conflict

Discussion in 'Other Linksys Equipment' started by soslink, Aug 5, 2008.

  1. soslink

    soslink LI Guru Member

    We have a LAN with Windows 2003 Server and XP Pro clients that are not connected to the Internet and our wireless DSL router is not on the LAN. We connect to the DSL router via our laptops when we want Internet access.

    Now we have the need to have one of the LAN PCs have Internet access so we purchased the Linksys WUSB54GC adapter. We are able to connect to the DSL router and browse the Internet but only if we disable the LAN connection.

    Here is our network topology:

    LAN:

    Statically assigned IPs: 192.168.1.x (Our server does not run DHCP)
    Gateway: empty
    Primary DNS assigned: 192.168.1.5 (this is the W2K3 Server IP)

    Wireless DSL Router: (NOT plugged into LAN switch)
    IP: 192.168.1.1 (factory default)
    DHCP enabled: YES

    Wireless Adapter in PC:
    Obtain IP & DNS automatically -- gets IP of 192.168.1.42

    It looks like we need to have the Wireless router on a different subnet, like 192.168.2.1 to get this PC to be able to use the LAN as well?

    Thanks for advice
     
  2. ifican

    ifican Network Guru Member

    Sometimes windows will do goofy things when it has more then one network connection. What it sounds like is your wired connection is primary and since your machine does not have a default gateway set for its primary connection it does not just automatically use the default gateway for the secondary adapter. If you input a default gateway for that one machine it should fix this issue.
     
  3. soslink

    soslink LI Guru Member

    I think I tried that but will try again to be sure. Would putting the wireless router on a different subnet 192.168.2.1 work? Also, is binding order on the adapters relavant?

    Thanks
     
  4. ifican

    ifican Network Guru Member

    With the way windows works perhaps changing the subnet might have an effect. However if you go to a command prompt and input "route print" (without the quotes of course). You will get the routing table windows has built and you should have a default route from the dsl router 0.0.0.0 192.168.1.1 or something like that.

    In regards to the binding order that is what i was talking about, because the lan is bound as the primary and the primary does not have a default gateway that is what i am talking about. Another thing that comes to mind is dns. It may be that windows is routing correctly its just not resolving and that is easy to test as well. Again from the command prompt input "tracert 1.1.1.1" and see if you get past your dsl router. If you do it a matter of dns not the default gateway that giving you grief.
     
  5. HennieM

    HennieM Network Guru Member

    I beg to differ from ifican: putting the wireless on a different subnet, and with that subnet HAVING the internet router as default gateway, would _definitely_ solve your problem.

    At current, your windows gets addresses on the same subnet for both LAN and wireless adapters, so it would use only the one it thinks best. Who knows what Win thinks best...., but most likely the one with the fastest connection. Anyway, to get to the default gateway assigned to the wireless - 192.168.1.1 - Win thinks it can send the request via the LAN adapter, so the request never gets to the internet router.

    Should you assign your wireless/internet stuff subnet 192.168.2.0/24 for instance:

    If your LAN (192.168.1.0/24) has no default gateway, and wireless (now 192.168.2.0/24) has a default gateway (the internet router at 192.168.2.1), Win's routing would immediately send the a request for an internet address to the router via wireless.

    If your LAN has a default gateway (say to another LAN), and wireless also has a default gateway, Win's routing would probably assign higher priority to the LAN default gateway, and try that first for an internet address. After a delay, Win would see that the LAN default gateway does not get to the internet, and then try the wireless gateway, which would put you on the internet.
    (The above might not be strictly true: Win might only keep the default gateway it was assigned last, which should be the wireless normally.)

    Similarly for DNS. If your LAN has a DNS server, and the LAN interface on the PC has that DNS address, it would probably try the LAN DNS server first. The LAN DNS server would then say "I cannot resolve www.google.com" (or whatever), and Win would then try the DNS server(s) assigned via the wireless's DHCP, which should be the internet router.

    Win sometimes have trouble with this "going over to the next DNS server", but usually works correctly if there are no more than 2 DNS servers specified on the PC.

    All this while the LAN stuff is merrily working as usual....
     
  6. ifican

    ifican Network Guru Member

    Heck disagree with me anytime its what prompts discussions that we all learn from :). Strictly from a routing standpoint the defaul route that windows receives from the dsl router should no matter what be the default route for any non directly connected devices. If you pull the route table it will have a default route, however as explained windows does not always act like a true router but its understandable as its not designed as such. Your point though is valid and being that the default gateway would be on a different subnet perhaps windows will unconfuse itself, though i have seen other wise. A prime example is we have wireless and wired connecections at work. I often times forget to turn off wireless and more often than not windows will confuse the heck out of itself because i was first on wireless. From any give router the above would have no bearing and it would just work. But i am very curious now whats going to fix it.
     

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