Subject: Re: very slow TCP connection on localhost
To: Manuel Bouyer <>
From: Kevin Lahey <>
List: tech-net
Date: 09/05/2006 21:09:40
On Tue, 5 Sep 2006 18:49:08 +0200
Manuel Bouyer <> wrote:

> On Tue, Sep 05, 2006 at 06:45:24PM +0200, Manuel Bouyer wrote:
> > [...]
> > Attached is the output of tcpdump -w on lo0 for this TCP connection.
> With the file attached, this time. Sorry

Yow, that's a weird trace.  I was just going to suggest that you
increase the socket buffer size, but that was before I saw the
retransmissions and other stuff in the trace.  Could you make a
trace that shows the three way handshake when the connection starts up,
so we can see the window scaling that gets set up?

(And, it'd be interesting to see what happens if you increase the socket
buffer size.)