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Hello, My hardware has two interfaces: a) ethernet - eth0 b) WirelessLAN - eth1. After power on, eth1 gets associated to WirelessLAN access point. Following is the network Setup: Hardware ...
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  1. #1
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    IP Routing : WirelessLAN and Ethernet in Same Network


    Hello,

    My hardware has two interfaces: a) ethernet - eth0 b) WirelessLAN - eth1.
    After power on, eth1 gets associated to WirelessLAN access point.

    Following is the network Setup:

    Hardware eth0 IP address: 192.168.254.254
    Hardware eth1 IP address: 192.168.254.253
    Wireless LAN Access Point IP address: 192.168.254.1
    test PC eth0 IP address: 192.168.254.102

    The ethernet interface of Hadrware and test PC is directly connected to Wireless LAN access point through ethernet cable. Hardware is associated to Wireless LAN access point through eth1 interface.

    Here is my hardware's routing table:
    Kernel IP routing table
    Destination Gateway Genmask Flags Metric Ref Use Iface
    default 192.168.254.1 255.255.255.0 UG 0 0 0 eth1
    default 192.168.254.1 255.255.255.0 UG 0 0 0 eth0
    192.168.254.0 * 255.255.255.0 U 0 0 0 eth0
    192.168.254.0 * 255.255.255.0 U 0 0 0 eth1
    default 192.168.254.1 0.0.0.0 UG 0 0 0 eth0

    Now, when ethernet cable is connected to hardware, I can ping 192.168.254.254 from test PC.
    When I removed ethernet cable from hardware, I cannot ping 192.168.254.253 from test PC.

    I think access point should forward the incoming packet from test pc to hardware's eth1 interface wirelessely.

    Where am I wrong? Is it related to Kernel's routing table? If yes, how to detect removal of ethernet cable from hardware and change routing table dynmically?

    Thanks.

    Regards,
    Sumit

  2. #2
    Linux Guru Lazydog's Avatar
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    Place your wireless and wired network on different subnets. Your system doesn't know how to route them. One Default GW per Network.

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    Robert

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    Re::IP Routing : WirelessLAN and Ethernet in Same Network

    Thanks for the response.
    Yes, I tried that scenario with different subnets and it also did not work.

    Now I need to perform the same scenario within same subnets, like our PC. PC can have ethernet and Wireless LAN card in the same netmask. I want test PC to ping both the interfaces and if anyone gets down, it should ping other interface.

    How should I make my system to route it correctly?
    I tried using route add -net option. It worked but finally only one interface can be pinged. If I disable one, it should ping the other or vice versa.

    Thanks.

    Regards,
    Sumit

  4. #4
    Linux Guru Lazydog's Avatar
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    Better question is why do you need this?

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    Robert

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    I need this because I don't want to loose network connectivity. So if anyone of network interfaces get down due to any reasons, the other network interface should be active. (Offcourse I cannot do anything if both goes down, but thats the worst case).

    When I print Kernel IP Routing Table, using route command, I can see Iface column for network interface.

    I would like to have entries for both these interfaces to appear under that column when they are in same network. Is it possible?

    Regards,
    Sumit

  6. #6
    Linux Guru Lazydog's Avatar
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    You should not have more then one interface per network working indepntantly of each other. Is this a home setup or business setup?

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    Robert

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    Re:

    Its a business setup.

    Isn't it possible?

    Regards,
    Sumit

  8. #8
    Linux Guru Lazydog's Avatar
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    Business setup? Really? Then you should be using a hot-standy if you cannot afford for the server to be down, not some jerry-rigged wireless setup. At the minimum you should be using 2 wired connections and sharing an ip address between them. Then use something like heartbeat to get the interface up and responding to requests.

    I have been running hardware 24x7x365 for over 10 years and it is usually the network coming into the building that dies so having more then one connection to a network isn't going to help you there.

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    Robert

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