[coLinux-devel] Networking corruption

[John L. <jo...@su...>]

When using ssh to transfer large files, or run real x apps, I've been 
getting "Corrupted MAC on Input" errors.  I've looked around the net to 
see what might cause this, and apparently, the MAC here is not the MAC 
address, but a CRC like mechanism that ssh uses to ensure data 
integrity. Most seem to claim that the problem comes from either 
corrupted buffers on the NIC itself(since it passed the CRC test) or 
poor memory handling in the network driver. 

I'm guessing that the TAP driver might need a little tweaking somewhere, 
does someone here know anything about it?  I might just see if I can 
look into the code myself, but I'm no networking hacker... 

Also, I find it interesting that some people seem not to see this at 
all.  I'm running windows 2000 professional here. Maybe the tap driver 
behaves a little differently?
Below are some tests that I ran.

John LeSueur

I've been trying to determine what's causing network errors, on large 
files, or at least get some kind of info about it, so I did the 
following tests.

using netcat, I made the following test:

in colinux:
nc -l -p 6434 | dd of=kernel-source-2.4.24_2.4.24-1_all.deb

on a redhat machine:
nc 192.168.0.40 6434 < kernel-source-2.4.24_2.4.24-1_all.deb

Then did an md5sum on the resulting transferred file

original:
1e7f3309aca976167648c8a813128021  kernel-source-2.4.24_2.4.24-1_all.deb

transferred to colinux:
7c2e08ac025865f8195a952170718e8b  kernel-source-2.4.24_2.4.24-1_all.deb

file sizes are exactly the same.

Then to see if corruption is random(very likely), I transferred the same 
files again.

original:
1e7f3309aca976167648c8a813128021  kernel-source-2.4.24_2.4.24-1_all.deb

colinux:
c969f5caaa6302b2f7a63c9ca3842e0d  kernel-source.deb

To make sure that it's not inside the kernel that we have errors(ha!), I ran

in colinux:
nc -l -p 6434 | dd of=kernel-source-2.4.24_2.4.24-1_all.deb2

in colinux:
nc 127.0.0.1 6434 < kernel-source-2.4.24_2.4.24-1_all.deb

files are the same.