On Friday 18 January 2008, Marko Kocić wrote:
> > Actually, as long as the interface is up, you can sniff traffic even if
> > it does not have an IP address. Emerge wireshark (somehow...), do (as
> > root) an "ip link set eth0 up" (or "ifconfig eth0 up") and run
> > wireshark. Start capturing packets, run dhcpcd from the command line (or
> > whatever DHCP client you use), and see what goes on the wire. You should
> > see DHCP discovery/offer/request messages, or maybe not all of them if
> > things are not working correctly. For each DHCP packet, look at the DHCP
> > payload details from wireshark (you can save the capture for later
> > viewing too).
> >
> > Then, start windows, install wireshark for windows, and do the same. To
> > force a DHCP negotiation in windows, open a command prompt and issue
> > an "ipconfig /release" followed by an "ipconfig /renew" (IIRC). Look at
> > the traffic captured after the /renew command, and look for obvious or
> > blatant differences between windows and linux in DHCP packets of the
> > same kind.
>
> Thanks for the info. I'll try that.
>
> Also, I just found by googling that there is dhcp client called
> net-misc/pump which
> have --win-client-ident option. I'll try that too.

I wonder if my similar problem is related to what you report here:  I am using 
dhcpcd and ifplug with my ADSL router, which acts as the dhcp server on my 
LAN.  For some reason ifplug does not always manage to get an IP address from 
the router and I end up with an APIPA address.  /etc/init.d/net.eth0 
stop/start gets it going again.  This problem only occurs if I disconnect and 
then reconnect the ethernet cable.  No such problem exists when I boot the 
machine with the cable already connected to the NIC.  I haven't changed 
timeouts or anything else from the dhcpcd defaults.  I have always attributed 
this problem to a somewhat slow dhcp server on the router.

As a note:  WinXP machines do not have any such problem.  Even though they may 
end up with a APIPA address, they will in minute or so drop it and acquire a 
10.10.10.XXX domain address from the router.  dhcpcpd does not seem to have 
this flexibility.
-- 
Regards,
Mick