CM1200 does not assign IP address unless Ethernet cable is unplugged and plugged back in

Question

I bought a CM1200 yesterday to replace a super-flaky SB8200. Unfortunately, the CM1200 only allows me to get an IP address right after cycling the Ethernet cable. This is a problem, as whenever I change settings my router reboots itself and I have to go cycling a cable to reestablish connectivity. There are no settings to speak of in the device configuration, so I can only assume that this is a firmware bug.

FURRYe38 · Answer

Swap the LAN cable between the modem and your connected device. CAT 6 is recommended.&nbsp;&nbsp;What device do you have connected to the modem? PC or External router? Mfr and model#?

zbrozek · Answer

Same problem reproduces with six different cables, including the brand-new one that shipped with the CM1200.

FURRYe38 · Answer

What device do you have connected to the modem? PC or External router? Mfr and model#?

zbrozek · Answer

I've tried two devices. One is plan-of-record, the other is for debugging.&nbsp;Debugging device is an ancient WRT54G. Plan-of-record device is a computer with an Intel NIC attached to a VM running pfsense. Right now whenever I change a setting on the WRT54G, it reboots itself. With the VM, if I ever reboot it, the NIC doesn't actually bring down the PHY - it just asks for a new IP on restart.&nbsp;It doesn't seem like there should be any connection between responding to a DHCP request and link history.

FURRYe38 · Answer

Any chance you have a more up to date router? Something to test with to see if the CM still hands out and IP with out having to unplug and plug in the LAN cable?&nbsp;&nbsp;I didn't see this issue with my 1200...

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CM1200 does not assign IP address unless Ethernet cable is unplugged and plugged back in

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