Subject: Re: [libssh2] #166: Some servers terminate connection due to large window adjustment

Re: [libssh2] #166: Some servers terminate connection due to large window adjustment

From: Daniel Stenberg <daniel_at_haxx.se>
Date: Thu, 25 Mar 2010 09:42:29 +0100 (CET)

On Thu, 25 Mar 2010, Jose Baars wrote:

> there is no use to enlarge the SSH protocol window above the TCP/IP window
> size of the socket.

Well, first I'm not so sure about that and secondly we don't know/check the
TCP window size so we're not in synch...

> The quick fix is the division by 10 and wouldn't break anything, although
> performance on really fast connections with RFC compliant SSH servers (any
> out there?) might suffer a performance impact.

I am the one who bumped the window sizes that much and yes I have successfully
tranfered many gigabytes using both SCP and SFTP with libssh2 to and from
openssh and it deals with the window sizes just fine and as the spec says.

I'm the one who bumped the sizes that much as I saw an increased performance
in doing so, but of course performance isn't worth sacrificed functionality.
It should be easy enough for anyone to measure what impact this smaller
maximum window will have, but I don't personally feel that I have the time and
energy to play around with that at the moment.

-- 
  / daniel.haxx.se
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Received on 2010-03-25