no IP from DHCP after docking laptop

Hi,

The network on my Dell Latitude D505 was working perfectly fine , using
DHCP to obtain an IP address from the campus network. Then I docked my
laptop into a D/port replicator. It didn't seem to pick up the network
connection when the cable was plugged into the port replicator, so I
undocked the laptop and plugged the network cable straight into the
back of the laptop...but I now can't get an IP address from the DHCP
server! When I changed my /etc/network interfaces from "iface eth0 inet
dhcp" to "iface eth0 inet static", I can get onto the network, so I
assume my ethernet card is okay. I just don't understand why, before
docking my laptop into the port replicator, I was able to obtain an IP
address and that after I docked it once, I cannot?? I've unfortunately
done the same thing to another laptop to see whether it was something
quirky about my own, but now both are affected!

In any case, I've tried: removing the module for my ethernet card
(rmmod e100) and reloading it, restarting the networking, rebooting,
cold rebooting, resetting the BIOS to the default, upgrading my kernel
(from Debian sarge 2.6.8-1 to Debian sarge 2.6.8-2). I just don't get
it....

This is my network card (lspci -v output):
0000:01:08.0 Ethernet controller: Intel Corp. 82801BD PRO/100 VE (MOB)
Ethernet Controller (rev 81)
Subsystem: Dell: Unknown device 2002
Flags: bus master, medium devsel, latency 32, IRQ 11
Memory at fcffe000 (32-bit, non-prefetchable) [size=4K]
I/O ports at ecc0 [size=64]
Capabilities: [dc] Power Management version 2


I'm not sure what other information I need to include....but any help
would be much appreciated! As well as advice on how to get the network
on the port replicator to work using DHCP (it's a pass-through
controller). I confess I haven't tried statically specifying an IP
address while docked on the port replicator.....

Thanks in advance!
g

> In any case, I've tried: removing the module for my ethernet card
> (rmmod e100) and reloading it, restarting the networking, rebooting,
> cold rebooting, resetting the BIOS to the default, upgrading my kernel
> (from Debian sarge 2.6.8-1 to Debian sarge 2.6.8-2). I just don't get
> it....

In your shoes, I'd probably try the following next:

- see if Knoppix (or similar linux-on-a-CD) can boot and get an IP
address. This will help you decide if it's an OS issue.

- run "tcpdump -n" or equivalent on the interface while restarting the
DHCP client. (I'm not a Debian expert, so I'll let someone else provide
details.) You don't necessarily have to understand what's going on, but
it would be helpful to know whether your laptop is even talking to the
DHCP server.

(E-Mail Removed) wrote:
> Hi,
>
> The network on my Dell Latitude D505 was working perfectly fine , using
> DHCP to obtain an IP address from the campus network. Then I docked my
> laptop into a D/port replicator. It didn't seem to pick up the network
> connection when the cable was plugged into the port replicator, so I
> undocked the laptop and plugged the network cable straight into the
> back of the laptop...but I now can't get an IP address from the DHCP
> server! When I changed my /etc/network interfaces from "iface eth0 inet
> dhcp" to "iface eth0 inet static", I can get onto the network, so I
> assume my ethernet card is okay. I just don't understand why, before
> docking my laptop into the port replicator, I was able to obtain an IP
> address and that after I docked it once, I cannot?? I've unfortunately
> done the same thing to another laptop to see whether it was something
> quirky about my own, but now both are affected!
>
> In any case, I've tried: removing the module for my ethernet card
> (rmmod e100) and reloading it, restarting the networking, rebooting,
> cold rebooting, resetting the BIOS to the default, upgrading my kernel
> (from Debian sarge 2.6.8-1 to Debian sarge 2.6.8-2). I just don't get
> it....
>
> This is my network card (lspci -v output):
> 0000:01:08.0 Ethernet controller: Intel Corp. 82801BD PRO/100 VE (MOB)
> Ethernet Controller (rev 81)
> Subsystem: Dell: Unknown device 2002
> Flags: bus master, medium devsel, latency 32, IRQ 11
> Memory at fcffe000 (32-bit, non-prefetchable) [size=4K]
> I/O ports at ecc0 [size=64]
> Capabilities: [dc] Power Management version 2
>
>
> I'm not sure what other information I need to include....but any help
> would be much appreciated! As well as advice on how to get the network
> on the port replicator to work using DHCP (it's a pass-through
> controller). I confess I haven't tried statically specifying an IP
> address while docked on the port replicator.....
>

Could the port replicator send a different MAC address and the campus
network be fussy about which MACs to let in?

--

Tauno Voipio
tauno voipio (at) iki fi