Hi,
I flashed ceroWRT 3.7.5-2 on router WNDR3800.

If I connect:
Cable Modem -> WNDR3800 -> Computer
I can't get access to internet by wire or wi-fi.

WNDR3800 in tab:
Status -> Overview -> Network IPv4 WAN Status shows Not connected
Ping from tab:
Network -> Diagnostics shows PING 8.8.8.8 (8.8.8.8): 56 data bytes ping:
sendto: Network is unreachable

But if I put another router between Modem and WNDR3800 I'll get IP address.
Only then everything works fine:
Cable Modem -> Old Router -> WNDR3800 -> Computer
and I can access internet by wire or wi-fi.

WNDR3800 in tab:
Status -> Overview -> Network IPv4 WAN Status shows normal IP address,
dhcp, net mask etc.
Ping from tab:
Network -> Diagnostics works fine

I've tried returning to default settings and reflashing ceroWRT, no luck.
Probably there's some little DHCP setting that prevents me from obtaining
IP address directly from Cable Modem.

Thanks for your time,
qkiel