Problems with wrong MAC address on port

RouterOS General
1

Hello,

First of all I do not claim this to be a RouterOS issue, but neither am I not aware I would have configured it that way.

I used to have a master/slave port configuration for ethernet ports 1 & 2 on my RB3011UiAS, which was transformed to a bridge configuration during one of th efirmware updates. Currently I am running 6.41rc52

Due to a network problem that appeared recently I was doing some packet traces and noticed packats that have a MAC address from AVM (Fritzbox) rather than Mikrotik. So IO disconnected my FritzBox, but stil saw this MAC address.

Actually the Fritzbox is attached to port 2, and port 1 inside the router took (or I did it?) the same MAC address as the router has. The bridge MAC address is still a Mikrotik one, port 2 also. Looking into the bridge host table I see th eFritzbox address on both ports (1 & 2). Checking ether-1 in th einterfaces list show sthat it has (as well as the 2 VLANs belopw) the AVM MAC address assigned

But I can’t find any place where I would be able to manually assign such an address. What am I missing ?

2

I did now reset the MAC address using the “Reset MAC Address” button in WinBox, but still don’t see how this address was changed in th efirst place.

3

Seems the MAC address can only be altered via teh terminal.

I remember now having altered the MAC address to match an AVM address due to identification problems over PPPoE with voip whit the Fritzboix being behind the MikroTik. I had to make th eprovbide believe he was speaking to the Fritzbox.

There seem to have been a change in RouterOS which fails my PPPoE setup whenever I change the MAC address on the PPPoE port (the ethernet port connected to the PPPoE modem). Whet happens is once I change th eMAC address, DHCPv6 will not get any reply anymore. I believe however that the sewrve sends the reply but the router does not forward it into the software. I will check this during th eweekend.

First I believe th eproblem was with the firewall wrongly matching th einterface due to the altered MAC address as I have a rule for DHCPv6 replies from the internet which also has to match the PPPOE interface (the virtual PPP interface this time). But this i snot th ecase as I don’t see the reply in the sniffer trace even if I remove th einterface from the rule.

As soon as I reset teh MAC address to its default DHCPv6 client gets its prefix as expected.