Strange DD-WRT problem

While I was trying to see why the time in my router running DD-WRT was out of sync (a couple of minutes ahead), the WAN connection lost its DHCP lease.  The cable modem appeared to be alright from the status LEDs, but the router would not get an ip address even after releasing or renewing the lease.  I tried powering on and off both the router and cable modem and was able to briefly get a private ip to at least see the cable modem, but then even that lease was somehow lost.

Next, I tried restoring the router's configuration to "factory" defaults.  It still wasn't able to get a lease.  Finally, I tried reloading from a backup of the firmware settings, and then the router was finally able to get a DHCP lease.

I'm not sure, but it is quite possible that the problem was actually on the Comcast side and not with the router.  Until this incident, the router's uptime was over 30 days.

Also, I discovered a workaround for fixing the time drift.  On the Administration->Management page, I added this to cron:

0 1 0 0 0 /usr/sbin/ntpclient -c 1 -s -h 0.us.pool.ntp.org