[coLinux-users] Invalid checksums

[Xavier B. <xav...@gm...>]

Hi,

I'm running CoLinux 0.6.2 on Windows 2000 SP4 to run a Debian image. 
I've got invalid checksums which makes impossible to run an ssh
session between the host and colinux.  I'm using a bridged ethernet
connection.

My configuration is :
<?xml version="1.0" encoding="UTF-8"?>
<colinux>
    <block_device index="0"
path="\DosDevices\e:\colinux\Debian-20040605-mit.ext3.1610mb"
enabled="true" />
    <block_device index="1" path="\DosDevices\e:\colinux\swap_512Mb"
enabled="true"></block_device>
    <bootparams>root=/dev/cobd0</bootparams>
    <image path="vmlinux" />
    <memory size="128" />
    <!--  <network index="0" type="tap" /> -->
    <network index="0" type="bridged" name="Marvell" />
</colinux>

A sample tethereal trace (host=192.168.1.100, colinux=192.168.1.102)
of a putty ssh connection:
No.     Time        Source                Destination           Protocol Info
      3 0.008588    192.168.1.100         192.168.1.102         TCP   
  1163 > 22 [SYN] Seq=0 Ack=0 Win=65535 Len=0 MSS=1460
      4 0.008769    192.168.1.100         192.168.1.102         TCP   
  1163 > 22 [SYN] Seq=0 Ack=0 Win=65535 Len=0 MSS=1460
      5 0.023884    192.168.1.102         192.168.1.100         TCP   
  22 > 1163 [SYN, ACK] Seq=0 Ack=1 Win=5840 Len=0 MSS=1460
      6 0.023902    192.168.1.100         192.168.1.102         TCP   
  1163 > 22 [ACK] Seq=1 Ack=1 Win=65535 [CHECKSUM INCORRECT] Len=0
      7 0.024081    192.168.1.100         192.168.1.102         TCP   
  [TCP Dup ACK 6#1] 1163 > 22 [ACK] Seq=1 Ack=1 Win=65535 Len=0
      8 0.024373    192.168.1.102         192.168.1.100         TCP   
  22 > 1163 [SYN, ACK] Seq=0 Ack=1 Win=5840 Len=0 MSS=1460
      9 0.024387    192.168.1.100         192.168.1.102         TCP   
  1163 > 22 [ACK] Seq=1 Ack=1 Win=65535 [CHECKSUM INCORRECT] Len=0
     10 0.024564    192.168.1.100         192.168.1.102         TCP   
  [TCP Dup ACK 9#1] 1163 > 22 [ACK] Seq=1 Ack=1 Win=65535 Len=0

As you can see, there are some packets with an invalid checksum and
others with a valid checksum.

The network card is a "Marvell Yukon Gigabit Ethernet
10/100/1000Base-T Adapter, Copper RJ-45" running at 100Mbps.

It only happens between the host and colinux.  On colinux, I can
flawlessly install packages and so on...

Any idea why it happens ?

Thank you,
Xavier Brouckaert