Subject: Re: New sysctl "net.listen_backlog"?
To: Marc Slemko <>
From: Todd Vierling <>
List: tech-net
Date: 09/14/1998 15:21:32
On Mon, 14 Sep 1998, Marc Slemko wrote:

: > The kernel default for this value would be 5, _but_ the definition of
: > SOMAXCONN in <sys/socket.h> would be changed to something intended to make
: > reasonable use of an increased value by default (say, 32).  Since listen()
: > silently reduces a larger-than-the-limit number automatically, this would
: > not interfere with program operation.

: What is any modern OS doing defaulting to something tiny like 5 or 32?
: That is very broken.

5 is known and expected, and very reasonable for a machine that _isn't_ a
server - it actually helps lower the chances of protocol level attacks at
listening sockets.

The ability to change that at run-time is what I'm proposing here.

-- Todd Vierling (Personal; Bus.