Cannot lease IP address after city power failure

The power company in my town reported that a "bad underground cable" was the cause of a 3 hour power outage on Sunday that resulted in loss of power within a couple miles radius of my service address. Since that time, my router has not been able to lease an IP address.

Performing a packet dump, I can see that DHCP Discover packets are being sent out by my router. I see DHCP Offer and DHCP Ack packets for various cable modems on the Comcast network, but none with a matching Transaction ID for the layer 2 address of my router. I have also tried plugging in other routers and devices directly to the cable modem with the same results.

I might guess that this was the first time in a while that some Comcast hardware in this area went through a power-cycle.  I'm smelling some configuration settings on Comcast hardware that never got saved to non-volatile memory, perhaps relating to a DHCP relay?

Any help is appreciated. Thanks.