MAC address questions

RouterOS Beginner Basics
1

I have successfully setup our first Mikrotik at our office. The configuration is very similar to projects we will deliver for clients. We will be furnishing same model router RB2011UAS. I made a backup of the office router to take to a clients and load there and modify as needed. Everything worked great after i reset the MAC on all the interfaces to the routers factory MAC to get rid of the clones from my office router backup. The problem i am having is that even though i reset all the MAc addresses on all of the interfaces, when i open winbox to connect, it always finds the MAC that was copied from backup. I have done this process 3 times and all routers connect via the same MAC in winbox. If i save login info for each router, they will all have individual identification, but same MAC address. How do i resolve this.

TIA

2

Do you mean that searching in Winbox is producing entries with the unwanted MAC? If you ping the RouterBoard from an attached PC which MAC address shows up in the ARP cache? (arp -a on a PC)

3

Are possibly using bridges with admin-mac configured?

4

yes, searching in winbox results in all 4 routers having same MAC address as original router whos backup i have used to restore the 3 new routers. i finged it and it has the unwanted MAC.

5

OK, winner winner chicken dinner!!! that is the issue. i went back to all the interfaces 1-10 and sfp and reset MAC addresses. i did not think to check the bridge. it has the offending MAC address greayed out. below it has the same address in the admin MAC field.

what is the purpose of this? i took the mac out of the admin window and the proper MAC came up in the MAC address window. what is the admin MAC window for and what MAC should be in it?

Thanks so much!!

6

Good to hear your problem is solved.

7

Because:

  • The default MAC address of a bridge is determined by the lowest MAC address of any of its ports;
    It’s very common to have bridges where ports join and depart dynamically (WDS, PPTP, etc.), and
    Some features break if you let a bridge’s MAC address change dynamically (see this posting for a good example).

As to what you are supposed to put in it, use a “private use MAC address.”

8

Another option would be defining the admin MAC static by choosing one of the assigned interfaces.
Than it never changes depending on PPTP and so on.

9

Yup, that will work, too, as long as you always remember to hand-edit the exported configuration if you ever have to swap out that unit for replacement or upgrade.