Rich Freeman on 3 May 2014 07:16:06 -0700

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Re: [PLUG] udp ports

On Sat, May 3, 2014 at 9:06 AM, The Nut <> wrote:
> It's unlikely that you're running out of UDP ports per se.  There are 64k
> worth of UDP ports available on a given server, usually about half of them
> are in the ephemeral range available for dynamic allocation.  You can view
> what your server's ephemeral range is set to using this command:

I'm open to correction here if I have things wrong, but this
limitation really only applies to programs listening for a connection.
 That is, you can't have more than 64k different listening sockets at
a time.

Connected sockets do not count against this limit.  You can have 64k
UDP connections open to each and every 2^32 IPv4 on the Internet if
you want to.

I might be missing some nuance here, but in general the number of UDP
port numbers isn't really a constraint on anything you'll see in the
real world.  I'd definitely check for artificial limitations set in
the kernel such as the number of open file descriptors first.

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