-1

From https://networkengineering.stackexchange.com/questions/57935/is-a-network-interface-supposed-to-have-no-more-than-one-mac-address/57937?noredirect=1#comment100988_57937

A network interface in a MAC-based network always requires a MAC address, virtual or physical. However, there are networks that are not MAC-based.

Doesifconfig show lo as a virtual network interface? ifconfig doesn't show its MAC address, does it mean lo has no MAC address, and the network of loopback IP addresses is not MAC-based?

Thanks.

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 2403613  bytes 138542051 (138.5 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2403613  bytes 138542051 (138.5 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
2

Since the lo interface is not associated with a hardware network interface (it's a virtual loopback interface), it does not have an Ethernet hardware address (MAC address).

Communication though the loopback interface is not MAC-based. No routing needs to take place to send packets between NICs.

  • Thanks. I updated my post. – Tim Mar 24 at 22:15
  • "No routing needs to take place to send packets between NICs." Does MAC need routing? Isn't routing a concept in layer 3, while MAC is in layer 2? – Tim Mar 24 at 23:09

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