Problems with proxy connections

Darren Tucker dtucker at
Tue May 23 22:05:28 EST 2006

Chris Rapier wrote:
> Could someone explain to me how the proxy command regression test works? 
> I'm having a problem as it relates to the HPN patch and could use a 
> little insight into what is happening in the proxy connections.

Typically, the proxycommand is an external command that connects to the 
server somehow (eg directly, via a SOCKS server).  Usually (but not 
necessarily) this will be over a TCP connection.

In the case of the regress test, the proxycommand is actually a shell 
script that invokes sshd directly (in inetd mode, so it speaks the SSH 
protocol on its stdin/stdout) rather than making some kind of network 
connection.  In fact the shell script wrapper isn't necessary, but it's 
there to redirect sshd's stderr for debugging purposes.

> So the question is, what is this connection type and are there any 
> thoughts on what the correct value would be to return?

Good question, but I don't have any answer other than "it depends". 
Your arbitrary value of 128k or similar sounds as good as any.

A similar issue would also occur if a platform did not support the 
SO_RCVBUF socket option (dunno if such a platform exists, now or ever).

Darren Tucker (dtucker at
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
     Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.

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