Intel EPro 100 Weirdness

[Matt Reynolds <debian@loopysoft.com>]

Hi all,
	I know this is more of a networking issue, but I'm thoroughly stumped and 
don't know where to turn anymore.
	My friend and I both bought IBM a21p laptops, with comparable memory and 
such, the major difference being that I bought the internal NIC/modem card 
with mine, and he bought his later.  After dumping some information from the 
laptops, and using Mr Becker's tools, the only major difference seems to be 
rev number for both of the cards (his is 12, mine is 9).  My card shows the 
following :
00:03.0 Ethernet controller: Intel Corporation 82557 [Ethernet Pro 100] (rev 
09)
        Subsystem: Intel Corporation: Unknown device 2408
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- 
Stepping- SERR- FastB2B-
        Status: Cap+ 66Mhz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- 
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 66 (2000ns min, 14000ns max), cache line size 08
        Interrupt: pin A routed to IRQ 11
        Region 0: Memory at f0120000 (32-bit, non-prefetchable) [size=4K]
        Region 1: I/O ports at 1800 [size=64]
        Region 2: Memory at f0100000 (32-bit, non-prefetchable) [size=128K]
        Expansion ROM at <unassigned> [disabled] [size=1M]
        Capabilities: <available only to root>

I believe his is the same, minus the rev difference.  We're both running 
Debian Unstable, we're both up to date, we're both running 2.4 kernels.  As 
I'll go into further down, we can even move the HD around and test with my 
hardware.

	Currently, he's seeing the following behavior:
1)  With a valid, routable static IP
He can assign the IP to the card, he can ping and connect to anything on the 
subnet, but the gateway (a cable modem at home, a linux box at work) doesn't 
respond to any connection.
2)  With a NAT'd, static IP
He assigns 192.168.1.66 to his card, he can ping everything locally, and the 
NAT server (a debian box) will connect him to the outside world, somewhat 
properly.  The NAT server is broken somehow in a different way where his and 
my linux boxes get weird errors with NAT (it's like the server becomes 
congested over time.  I'm using the debian NAT packages).  Regardless, his 
NIC performs like mine does.  We can get some data for a while, then it dies, 
but he can still connect to the outside world, briefly.
3)  With any IP configuration under windows
The NIC works perfectly.

I can get my card to work fine pretty much everywhere minus behind his NAT 
server.  I know the IPs are valid because we can configure his debian install 
on his HD, plug it into my machine, and it works fine.  We've done several 
tests, mainly involving recompiling the kernel, making sure the drivers work, 
then swapping hardware.

We've tried Intel's latest drivers as well, to no avail.  We've tried using 
2.2 kernels.

I'm at a loss to explain his errors.  If you have any suggestions (like 
a better place to post this), I would greatly appreciate them.

Thanks, 
Matt Reynolds