Why Omega2s+ have identical MAC and IP addresses on ETH and WiFi???



  • Why my Omega have identical MAC and IP addresses on ETH and WiFi???
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  • @Alexandr-Didenko I wish I had an answer for you. However I wanted to add that I find it fascinating and wonder the same.

    I can buy using the same MAC address as connecting to the device wired or over-the-air is using two different physical media. However the same IP is possibly problematic as a router may (or may not) have both paths in it's routing table. Perhaps routers handle such redundancy with ease, but I do not know.

    Now a question for you. Are you using a dhcp server that is provisioned to assign the IP addresses as such? Otherwise are you using whatever default dhcp automatic IP assignment service that is provided by your router?

    Anyone sharp in routing please chime in.

    --Bill



  • I suspect they do this to save money. There isn't a compelling reason to have an Onion on both WiFi AND Ethernet at the same time as the chip itself isn't that powerful, so the only problem it would solve is to allow the chip to be on two different subnets at the same time. The network speed won't improve much by having both connected. I suspect it's a trade off they chose to take advantage of.

    DHCP servers generally use MAC addresses for association in a database. It gets the MAC, stores some association data, and then sends out the response package. Since the connection TO the DHCP server is functionally anonymous from the requester, using MAC provides a very easy way to store associated data for lease continuation and what not. What you are seeing is two requests from two different interfaces into a DHCP server which just sees the same request twice, so it sends back the same results twice.

    There isn't much you can do about this, but the question would be, do you need both active at the same time? If not, turn one off.


  • administrators

    Each Omega2 device (includes through-hole and SMT models) is allocated 3 sequential MAC addresses.

    Since June of 2018, the allocation schema has been the following:

    • ra0 - the Omega's WiFi AP - matches the MAC address on the sticker
    • eth0 - ethernet port - is ra0 address + 1
    • apcli0 - Omega's WiFi client - is ra0 address + 2

    Some devices do not follow this schema and there are MAC address collisions between eth0 and apcli0.
    We're looking into a fix for this, but in the meantime, there's a workaround:

    // initial MAC Addresses
    root@Omega-F195:~# ifconfig | grep HWaddr
    apcli0    Link encap:Ethernet  HWaddr 40:A3:6B:C0:F1:96
    br-wlan   Link encap:Ethernet  HWaddr 40:A3:6B:C0:F1:95
    eth0      Link encap:Ethernet  HWaddr 40:A3:6B:C0:F1:96  // duplicated address
    ra0       Link encap:Ethernet  HWaddr 40:A3:6B:C0:F1:95
    
    // adjusting the MAC addresses and restarting the network interfaces
    uci set network.wan.macaddr='40:A3:6B:C0:F1:97'
    uci commit network
    /etc/init.d/network restart
    
    // after network interface is restarted, MAC addresses are adjusted:
    root@Omega-F195:~# ifconfig | grep HWaddr
    apcli0    Link encap:Ethernet  HWaddr 40:A3:6B:C0:F1:96
    br-wlan   Link encap:Ethernet  HWaddr 40:A3:6B:C0:F1:95
    eth0      Link encap:Ethernet  HWaddr 40:A3:6B:C0:F1:97  // fixed address
    ra0       Link encap:Ethernet  HWaddr 40:A3:6B:C0:F1:95 
    

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