reply to NorCal John
Re: [HSI] Which modem -- Motorola 6121 or 6141 I would suspect that it's a configuration issue with the E4200 why it he couldn't get it to work. As a DHCP request from that device is the same from the old D-Link.
I have the Linksys E4200 v1 as well and it works just fine with every modem I've ever had in the past year+ since I've had it. My guess was the modem had locked to the PC MAC address and then wouldn't allow the E4200 but they said they rebooted everything so I dunno. Shouldn't be a problem with the Airport either as it's using the same standards that's been in existence for years as well.