Subject: Re: very slow TCP connection on localhost
To: Steven M. Bellovin <>
From: Manuel Bouyer <>
List: tech-net
Date: 09/06/2006 16:52:58
On Wed, Sep 06, 2006 at 10:48:08AM -0400, Steven M. Bellovin wrote:
> The retransmissions are, I suspect, the key.  If TCP has to retransmit,
> it's because a packet or its acknowledgment got lost;

Or because the remote end took too much time sending the ack.

> TCP in turn
> interprets that as due to congestion and backs off.  The question, then,
> is why packets are getting lost.  Does 'netstat -i -d' show any drops on
> lo0?

No, the count it 0. Real interfaces don't have drops either.

Manuel Bouyer, LIP6, Universite Paris VI. 
     NetBSD: 26 ans d'experience feront toujours la difference