Setting MAC on interface vs. vif

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?

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.

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: