Verizon FiOS → Remote DVR & Onscreen CID worked with LAN to LAN...briefly

I recently got FIOS and, after making sure everything worked with the default setup, put together a LAN to LAN style setup with my WNDR3700 running OpenWrt as primary and the ActionTec behind it. I set up port forwards for 4567 to the Actiontec and 63145 and 35000->8082 to my one STB. I was happy to see that both onscreen Caller ID and Remote DVR worked properly.

...Until today, when (despite my not having changed anything and my external IP having remained the same) they both stopped working. Does anyone have any tips for what to do next? I've seen mentions of IGMP, but no details from anyone who actually said that enabling IGMP proxying fixed their issue.

I suppose my questions are: why did it work at first (when it usually doesn't in this configuration?) And why did it stop?

I can't tell you why it did work for a while. It's actually surprising to me that it worked at all.

The only configuration that is known to work reliably with called id and remote DVR is the three router configuration (option #8 in the trade-offs FAQ).

IGMP has nothing to do with this.

I'm hoping to avoid the three router configuration...I've seen a post or two by people who had CID/RDVR working with two router configurations, but nothing really in-depth from a networking perspective, more just 'It works!'

Well, I set up DHCP impersonation as described here: »Verizon Router DHCP Client Impersonation and renewed my lease, disabled CID, rebooted the box, brought it back up, re-enabled CID, and went into the troubleshooter, and the test CID showed up fine. A call from my cell phone also worked, and I'm now able to get into Remote DVR again as well.

"Counter-intuitive" would be an understatement at this point, but at least I have an idea for how to give it a good kicking when it starts acting up. At least my internet connection has been rock-solid.