Is there any chance to know the mac address of computers connected to the ethernet interfaces of CRS-s, even better the IP address 
?
sniff traffic… 
Well, I have configured it as a switch, all interfaces are slaves to ether1, and I have disabled connection tracking on firewall. So it is not possible to sniff traffic.
I was hoping that the switch would learn and know the mac addresses of the devices attached to it, as a matter of fact it must do it since it is considered a Layer3 switch. But where to find this info?
Create a bridge and put the port in question on it.
It will allow you to see the MACs under bridge/hosts.
I use a permanent bridge on the master port. Fast path will minimize the impact of the bridge on the system performance (it will do Gb traffic on that port without any issues).
And just get the port out of the switch and move it temporary to the bridge.
Take care not to lock yourself out of the device if it is in a remote location
Kind of a workaround, but shouldn’t the switch learn the mac addresses of the devices attached to it? This information got to be somewhere on it . MikroTik could kindly make it available.
The information is “in” it, the problem is, can it be read from the switch chip, and if yes, what amount of resources would it require…
I don’t think that collecting 24 mac addresses is that much resource hungry. If the switch can survive a bridge interface, which is a “software” interface, and gather information from it, then …
I’m not thinking about the router, but about the switch chip. Reading the switching table (again, if possible, we don’t know that) could disrupt normal switching.
Then again, this would make a nice feature request for the CRS series.
It should “learn” MAC addresses and store it in the switch chips forwarding database (FDB). In winbox I can goto the switch menu, FDBs and see all the learned MAC and what port learned from in the Unicast FDB tab
@rwaters
Nice spotting, that was it