How to have open more than 65k concurrent connections?

Thu Oct 14 19:58:41 UTC 2010

On Thu, 14 Oct 2010 12:54:05 -0400
Greg Whynott <Greg.Whynott at oicr.on.ca> wrote:
> this has nothing to do with ports.    as others have said,  think of
> a web server.  httpd listens on tcp80 (maybe 443 too) and all the
> facebooker's on earth hit that port.  could be hundreds of thousands,
> and only one port.     Available memory and open files will be the
> limiting factor as to how many established connections you can maintain
> with one host,  providing there are not any external limitations such
> as port speed.

You are correct.  Brain fart here.  I actually had to pull Stevens off
the shelf for a quick refresher.  Of course, every TCP connection is
different but only includes one port on the server.  The five-tuple
that defines the connection includes the remote host (client) and port
which is always unique at any one time.  Other than local resource
limits the total combinations is technically 256**6, i.e. every IP
address times the number of ports.  That's not even including IPV6.

Still off-topic here though.  The OP still needs to find the correct
group to figure out his real problem.

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