Also, to only allow certain destination networks to use the backup link if the primary link is down?
My situation is my home's alarm system uses IP to report burglary/events to the monitoring station. So under normal situations, Id like all traffic to use PPPoE and the GSM modem just sits there in standby. Connected to the cell tower network, but unused. I want my Tomato router to be able to fail over to GSM if my internet is down, BUT to only allow traffic to/from the monitoring station to use the backup GSM link if the primary PPPoE connection is down. (GSM has usage costs)
Im currently using a ND version on my older nonUSB linksys, so I'd need to upgrade routers.