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.
Best Answer
I encountered this same issue. The SB6141 only seems to give out one DHCP address when connected to the Internet (Comcast). First I connected my laptop PC directly to the modem, and it had Internet access fine. But then I disconnected the laptop and plugged in a Linksys 1900AC router. No DHCP address for the router, and the modem still had the MAC address of the laptop associated with the DHCP reservation. Resolved by powering down the cable modem and the router, and ensuring the cable modem and router were connected via ethernet. Then powered up the cable modem, then powered up the router. Now the cable modem sees the router and vice versa and have internet access through the router. Did not have to change address spaces