[OpenIndiana-discuss] weird packet garbling problem

[Bob Friesenhahn]

On Sat, 2 Feb 2013, Edward Ned Harvey (openindiana) wrote:

>> From: Jim Klimov [mailto:jimklimov at cos.ru]
>>
>> Basically, the workaround for us was to enable this line in /etc/system:
>>
>> set ip:dohwcksum = 0
>
> Oh well, thanks for the suggestion...  Unfortunately, didn't make any difference...

Unless TCP is offloaded from the kernel (so that checksums are in an 
adaptor card), it is exceedingly difficult for wrong data to pass 
TCP's checksumming and get passed up to the socket that SSH uses. 
However the other end, or an intermediary (e.g. router), can send 
certain TCP packets (and/or ICMP packets) which cause the connection 
to be aborted.  The using software may not be properly prepared to 
deal with TCP connections going away at some random time and may 
mis-diagnose the problem.  This is particularly an issue with software 
using the poll() system call, from which state changes need to be 
evaluated in a particular order or else the wrong diagnosis will be 
made.

Regardless, PUtty is Windows sofware so it is subject to Windows 
TCP/IP stack behavior.

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/