Sure enough, the configuration worked but died every 8-12 hours. The modem and router work fine independently, but together they are not a happy couple.
I was determined to get things working tonight. In preparation, I brought home an extra DSL modem and Airport Extreme from the Crowd Favorite office and I picked up a Linksys E2000 on the way home – just in case.
Step one was to swap out the modem – this actually appears to have done the trick. After rebooting the router, everything seems happy without the fiddling and dozens of restarts that were previously required to coax it into making a connection.
The hardware (DLink DIR-655 and Actiontec M1000) is the same combination that has been working in the office for the voice network for the last 6 months or so. I guess I’ll find out later tonight or tomorrow if I’m done or if I start cycling more hardware into the mix.