Hello, I've tried to make second gateway on mikrotik, and i've got some questions about it.
My configuration:
wan1 (main): PPPoE connection via ethernet, real static IP
wan2 (backup): adsl link via modem (dynamic IP, modem works as router, so mikrotik gots virtual IP)

questions:
1) if i do 2 routes with different distances, and fails something behind gateway, this version doesn't see this problem (gateway responds, MT thinks, that everything's OK), how to avoid it? Should I use NETWATCH?
2) check gateway: ping. I've set this option, added firewall output rule to log pings to gateway, waited some time and nothing happened, after that i've uset /tools ping [gateway] and got log records, that router had pinged gateway. Now i'm trying to figure out how often MT pings gateway to check connectivity?

IF you only want to use the backup when primary fails, it is very simple. Set the PPPoE connection to accept default route which will have a distance of 0. Then add a static default route to the second connection and specify a distance of say 5.

This will use PPPoE connection unless it fails - in which case it fails over to backup

See the Wiki is an example: http://wiki.mikrotik.com/wiki/Two_gateways_failover