Hi, I have the following situation:

Machines A, B, a router and a cable modem.

When connected directly with the cable modem, machine A get its
own IP address.
When connected directly with cable modem Machine B can´t get its own IP address. (it never renews the ip).

When I plug both in the router, only machine A gets its own fake ip, and none of them connects to the Internet.

When I try wan/dhcp renew on the router it says: dhcp conecting ... and then dhcp client disconected.

Only machine A can talk to the router.(192.168.0.1).

The router has cloned the mac address of machine A.

Could a NIC(machine A) be in a state where it can communicate with the router but not with the cable modem when pluged directly? I am thinking about trying a new NIC, but it doesn´t seem right that a NIC is good enough to comunicate with a router but not good enough to get an IP through the cable modem.

Thanks,

Rafael