DHCP trouble with cable modem

[Bryan A. Zimmer]

Hello, friends.

I am not new to networking and configuring desktop PC's in Fedora and
W*ndows, but I have a problem that is at least in part due to
unfamiliarity with DHCP.

Here's the problem: I have a friend who also uses Comcast broadband
cable internet. He uses Fedora almost exclusively, unless he can't
connect to the internet, in which case he switches to W*ndows XP.. (It's
as dual boot desktop).

In W*ndows, he never has problem receiving an IP address from the DHCP
server. He just configures the interface to use DHCP and, bingo! All the
network configuration info he needs is passed right to his8k machine.

In Fedora (both versions 7 and 8), he has chronic trouble getting
connected to the internet. At boot time, the attempt to start up the
interface "eth0" by requesting an IP from the DHCP server seems to fail
about 80% of the time, even more lately. Yet I see no obvious hardware
glitches, and the software configuration is vanilla-out-of-the-box.

As his closest "guru" (I try my best), I have tested different ethernet
cables, ethernet cards, the software configuration, all fine. The cable
modem itself was swapped recently as well. Nothing has changed All the
should-be-obvious problem variables seem perfectly fine. 

I suspect there is some subtlety of the hardware viz-a-viz Fedora that
is causing his "eth0" interface not to either give or receive the proper
signals to the cable modem, so the attempt to get an IP address usually
fails. 

In W*ndows XP, there is never a problem. The ethernet card gets the
address and my friend is on the internet in no time flat, every time.

I have a nearly identical setup in my home, and have no problems with
DHCP under Fedora. I don't know why this is. 

I am hoping and praying that one of you net config wizards can point me
rto the corrent config files or log files or online documentation:
anything that might help

thanks in advance

Bryan A Zimmer
(BAZ)
please respond in this group of privately to:
zimmer (dot) bryan (at) gmail (dot) com