I work with the installation of cable modems, and I am surprised at the number of Macintosh computers (especially new iMacs) that cannot immediately obtain and IP Address. To solve, we try some seemingly silly things like making AppleTalk inactive (and then activating it again), or changing the port AppleTalk is using. Sometime we have to trash the TCP/IP Preferences, boot using the Mac OS x.x All extension set, or play with the 'Load only when needed' checkbox (selecting or deselecting it) before the Mac obtains an IP Address. Most often we see this problem with the Built-in Ethernet port, despite the presence of the Ethernet (Built-in) or the Apple Enet extensions.
I have two questions. First - can anyone explain why this problem seems so prevalent? Second - are we missing some troubleshooting steps that would help us quickly identify and resolve this problem?
We support Mac OS 7.6 and above, use DOCSIS cable modems from 3Com & Toshiba, connect the cable modem directly to the computer (not through a hub), and have no TCP/IP settings to speak of since our DHCP server also supplies the DNS info. We create a new TCP/IP configuration, set to Connect via Ethernet & Configure Using DHCP server, and leave all other fields blank).
Any helpful information would be greatly appreciated.