Setting MAC on interface vs. vif

General questions
1

I’m not using the “home central” provided by my ISP, instead the fiber goes though a media converter and straight into VyOS. The NIC is passed through Proxmox into the VyOS VM.

For this to work; I have to spoof the MAC address of the “home central” to the WAN interface in VyOS, and create a VLAN.

This is my interface config:

 ethernet eth1 {
     description WAN
     hw-id dc:xx:xx:xx:xx:xx
     mac 98:xx:xx:xx:xx:xx
     vif 102 {
         address dhcp
         firewall {
             local {
                 name OUTSIDE-LOCAL
             }
         }
     }
 }

This works, if I set the MAC address on vif 102, it doesn’t seem to work.

I’m curious how setting a MAC address on the interface vs. the vif works. What actually happens when setting a MAC on the virtual interface? The MAC is a physical address, does it make any sense to define it on a virtual interface?

Does my ISP “see” the MAC address on eth1 or eth1.102?

2

Normally, tagged frames (i.e. using vlan) will use MAC address of parent interface, the hardware NIC.
If you want to overrule the MAC, this should be done on the parent.

3

Thanks for you reply. That is as expected.

So, even though the MAC address can be configured on a virtual interface; it’s probably just ignored.

Hm, I think I need to backstep and redo some of my ISP SFP module testing. Not sure why this didn’t occurred to me during that testing :man_shrugging: