I'm trying to help a friend remotely with an Internet connectivity problem. His internet went down this morning and the cable company had him switch to a Motorola Surfboard SB6141 modem from an older model Surfboard. It seems to be struggling to acquire a DHCP lease. On either of his Macs, when hooked up directly, it typically seems to take trying to force the computer to acquire a DHCP lease several times before it finally works. Mysteriously, however, when we hook the SB6141 up to a router even multiple attempts to renew the lease never leads to the router acquiring the lease (and this was true with his original Linksys WRT54G, a new Linksys E1200 and a new Linksys E2500). The routers consistently report an IP address of 0.0.0.0 (i.e., they haven't received any DHCP information).
Since the latter two routers were brand new, I don't think the router could be at fault and, normally, I've found that this sort of setup is a straightforward one that doesn't require any odd settings. Is there anything peculiar about the SB6141 that might be interfering with a normal router configuration? I'm wondering if the fact that the DHCP process seems less than smooth when directly connected to the computer indicates that there is something amiss with Charter's DHCP server.
UPDATE: To clarify, the routers are routers with all of the settings set to the OEM's factory settings. Normally, in such a case, the router would seemingly just start working with a cable modem and pick up a DHCP lease, which is what is puzzling here.