How does a router handle MAC addresses?

meash December 8, 2011

I read an article here on how routers work:


I think I get it, but I noticed the article doesn’t mention MAC addresses. Isn’ that important for a router to know? Does a router maintain a MAC table like a switch? Does the router also record the MAC address and Internal IP as packets leave the network? Does it have to make an ARP request every time to forward incoming packets to the requesting computer?

  1. Mike
    December 8, 2011 at 10:01 pm

    A router is a Layer 3 (Network Layer) device so technically it doesn't have to concern itself with MAC addresses to operate and fulfill it's function.

    The reason most or pretty much all routers do store MAC addresses is because they offer multiple network ports which operate on switching level (Layer 2, Data Link).

    Another point is that most "routers" you'll find in peoples home are so called residential gateways which combine the function of several devices (modem, gateway, router, switch) and therefor operate on various layers.

    In case your "router" has WiFi capabilities MAC addresses are also required for the Wireless Security (MAC filtering).

  2. Anonymous
    December 8, 2011 at 2:38 pm

    each port on a router has its own mac address, the reason the router has to have seperate MAC addresses, is because each device connected to that router has IT's own MAC address, so the router will say this packet  belongs to the device with XX:XX:XX:XX:XX:XX MAC address, and the routher will pass these frames to and from via using the MAC address through that particular port only with that device. So the MAC addresses are used for the hardware detection when sending packets, and the IP address is used for network location.