2 Replies Latest reply: Nov 28, 2011 6:26 PM by ProfessorPain
williakz Level 1 (0 points)

Recentlty, I had a nightmare trying to install a new Airport Extreme (fifth generation) into a plain jane Comcast-iMac hardwire setup. Applicaton was to provide secure net for video streaming to Xbox and for printing as well as guest network for, uh, guests. After a struggle, I found both the problem and the fix.


Comcast modem direct wire to iMac was solid, but modem to Extreme WAN was no go with either wireless or wired connection between iMac and Extreme. After a few choice words hurled at the obviously incorrect "Ethernet cable not connected" message reported by the Extreme, it finally dawned on me to listen to what I was being told.


If the Airport Extreme couldn't see the cable going from its WAN port to the Comcast modem, then either my cable was bad or the two devices were "failing to communicate." I knew the cable was good (I tried both known good Cat 5E and Cat 6 ones), so it had to be the devices. Then, I remembered they first had to do a little dance (autonegotiation) to decide at which Ethernet speed (10/100/1000Mbs) to talk to each other. I found the settings page that controlled this process and switched it from Autonegotiate to 100Mbs Full Duplex and voila!


Comcast modem was Ubee DDM3513 (standard equipment for Comcast basic hardwire installation).


Hope this helps someone else.

Airport Extreme (5th gen)