DHCP trouble with cable modem

Phil Meyer pmeyer at themeyerfarm.com
Mon Feb 4 19:14:25 UTC 2008

Bryan A. Zimmer wrote:
> 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.

We see this all the time at the office with systems that dual boot.
The DCHP server will see the Linux network as a different one than the 
XP one, even though the MAC address is the same (of course).

We have even experimented with using the exact same name on both, but it 
still offers a different IP to Fedora as it does to XP.

On some router/firewalls, they will REFUSE to give out the same IP to a 
different host.

Since the XP and Fedora partitions ask differently, and since some folks 
have only one IP address available from their ISP, or other DHCP 
service, the Fedora partition simply will never get an IP if XP was 
booted first, and vice versa.

I do not have a solution, only an observation, but perhaps others 
smarter than I can clue in on the different DHCP requests and offer a 

At work, we simply expect and plan for dual boot systems to eat two IPs.

Good Luck!

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