Subject: Re: TCP socket buffers automatic sizing
To: None <>
From: Blair Sadewitz <>
List: tech-net
Date: 07/21/2007 20:29:17
I should note that, as Steve Bellovin reported, I've gotten roughly
the same performance improvement simply by increasing the socket
buffer size.  Of course, this can be a waste, but waste is always
relative to reward. ;)

As I said before, I haven't tested this systematically, but with
ftp/http transfers, it seems that I don't notice much benefit until I
hit around 1MiB/s.  At ~2MiB/s, downloads from a site nearby seem to
run on average about 25% faster.

I wonder if there have been any reports of this feature being abused
as you describe on FreeBSD hosts for e.g. DoS attacks.

There is also some interesting stuff at (the corresponding FTP URL has
tarballs if the link to the file you want is broken).  There's lots of
code for NetBSD, albeit from around the 1.6.2 days.