Do VLANs have to have different MAC's?

Installing and Using OpenWrt
1

Hello! I was just looking at kernel log, then saw a bunch of

[2199979.100022] br-lan: received packet on lan2 with own address as source address (addr:xx:xx:xx:xx:xx:xx, vlan:15)

This address was the MAC of the router. I have a few vlans, I just let MAC to be default, which is identical for all of them. I wonder if it was bad: I used to set different MAC for each VLAN on my old routers, but someone said it’s not necessary, so I stopped doing it. chatGPT says it’s bad, and could be one of the causes of dhcp delay. (though I have some other reasons that dhcp is slow at first) Is it true? I don’t understand how it could be “bad”, it should be either totally fine, or totally wrong, that I should be getting noticeable problems right away.

Do I have to change MAC? I would appreciate your info!

2

No. You may want to change the MAC for privacy/security reasons but it is not required.

You only need change mac if its a MACVLAN which is different from VLAN (802.1q).

The kernel message described could be caused by a cable loop.

Are you using any switches?

3

Thank you for clarifying ! Yes, I have several switches, and after posting the question, it occurred to me that one switch causes this because of weird cables I use (no alternative!). I have to go and reboot that switch…… I think that was it….