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Subject: Re: performance issues
From: Wietse Venema (wietseporcupine.org)
Date: Tue Jun 06 2000 - 11:50:34 CDT

Brad Knowles:
> Hmm.... Actually, it's not kernel tweaking per se. It's
> changing the sysctl(8) parameters for net.inet.ip.portrange.first
> (currently at 1024) and net.inet.ip.portrange.last (currently at
> 5000).
>
> It's nice that I can change these things without having to
> rebuild the kernel or reboot, but it's a PITA that they are set so
> low by default. Sigh....
>
> I'm thinking of changing these to 7000 and 65535, respectively.
> Does anyone else on this list have experience with changing these
> parameters, and could offer some advice?

I see no good reason to change the lowest port from 1024, which is
the lowest unprivileged port number on UNIX.

On the other hand, Solaris has used {tcp,udp}_smallest_anon_port=32768
and {tcp,udp}_largest_anon_port=65535 for ages, so you can expect
such ports can talk to remote sites or else they would have changed
that (to find out, use: ndd /dev/tcp tcp_largest_anon_port etc.).

        Wietse