[tulip] KNE111TX arp problems

[Tom Huckstep]

I have two computers linked with a crossover cable between two
KNE111TX NICs.  henry is my main workstation, and maxwell is a old
system that I don't always have turned on.

After system boot everything is OK, and the network connection is
fine.  Often though, if I do an ifup eth0; ifdown eth0 on either
system the connection is broken, because one system or other cannot
find the hardware address of the other card. e.g.:

henry:/home/tom# ping maxwell
PING maxwell (192.168.0.2): 56 data bytes

--- maxwell ping statistics ---
2 packets transmitted, 0 packets received, 100% packet loss
henry:/home/tom# arp
Address                 HWtype  HWaddress           Flags Mask            Iface
maxwell                         (incomplete)                              eth0
henry:/home/tom# cat /proc/net/arp
IP address       HW type     Flags       HW address            Mask     Device
192.168.0.2      0x1         0x0         00:00:00:00:00:00     *                 eth0

Whilst maxwell has the correct arp entries.  If, however, the link is
working properly I get the correct entries in both.

I have looked at the activity lights whilst trying to ping from both
machines.  Keeping to the above example, if I ping to maxwell from
henry only one light flashes on henry and none on maxwell, which
suggests that henry is transmitting, but maxwell won't pick up its
ethernet packets.

If I ping to henry from maxwell one light on maxwell flashes and two
on henry, suggesting again that maxwell can't see henry's packets, but
henry can see maxwell's (because maxwell has the correct arp entries).

As an example, it breaks if I reboot henry whilst maxwell remains on.
There doesn't seem to be a lot of predictability about this.  There is
littlerepeatable behaviour e.g. varying times between the ifup;
ifdown, or if I ifup on one system before ifup on the other seems to
work sometimes and not at other times.

Am I just missing something basic about ethernet here, or is there a
deeper problem?  Has anyone else experienced anything like this?

I would be grateful for any information relating to this problem.

Tom Huckstep

*---- Related conffiles ----*

tom@henry:~$ cat /etc/hosts
127.0.0.1       henry   localhost
192.168.0.2     maxwell

tom@maxwell:~$ cat /etc/hosts
127.0.0.1       maxwell localhost
192.168.0.1     henry

tom@henry~:$ cat /etc/network/interfaces
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)

# The loopback interface
iface lo inet loopback

iface eth0 inet static
        address 192.168.0.1
        netmask 255.255.255.0

tom@maxwell:~$ cat /etc/network/interfaces
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)

# The loopback interface
iface lo inet loopback

iface eth0 inet static
        address 192.168.0.2
        netmask 255.255.255.0