How to have open more than 65k concurrent connections?

Thu Oct 14 16:41:10 UTC 2010

Jorge Amodio (jmamodio) writes:
> you have only 16-bits for port numbers.

    65k port numbers != number of connections.

    The number of open connections (if we're talking TCP) is
    limited by the number of max file descriptors in the kernel
    (fs.file_max).

    See also:

    http://www.network-builders.com/maximum-simultaneous-network-connections-t56317.html

    You could have hundreds of thousands of connections to
    the same (destination IP, destination port).

    In practice, there are other limitations:

    http://www.kegel.com/c10k.html is good reading, even though
    it is a few years old.