Does the Routeros Software let you configure loop back interfaces ?
I use them when building my mesh network as interfaces that are always up and avalible, and I cant find how to set them up on the routeros system.
according to RFCs a IP device is supposed to always listen to the loopback. MT follows teh RFC’s so you do not have to do anything to make the loopback function.
It will however not show in the list of IPs which might be what is confusing you but then when your dealing with some other OS’s they don’t show it either but yet the loopback is always there.
So feel free to do any tests against 127.0.0.1 it will always answer you on the MT box.
I would like to do my own loop back addresses like on cisco kit I can have an address assigned which is injected into the routing table to stableise my dynamic network.
Not just the local 127.0.0.1 loop back, I used to do it on linux with Zebra.
Actually, I have found that if you create a bridge with no members, it functions as a lovely loopback.
Very useful for announcing a host route via OSPF (one which will be reachable regardless of what interfaces are actually up, also nice for IPIP tunnels), and for creating nice black holes.
–Eric
cool cheers,
How did you work that out 
I noticed that addresses attached to a bridge interface continued to respond, even after I removed all ports from that bridge.
–Eric