net.inet.ip.portrange.randomized=1 hurts

Andre Oppermann andre at freebsd.org
Tue Jun 1 13:44:59 PDT 2004


Mike Silbersack wrote:
> 
> On Tue, 1 Jun 2004, Dmitry Pryanishnikov wrote:
> 
> >  The main question is: how to prevent this situation? Of course, as a
> > workaround I can set net.inet.ip.portrange.randomized to zero, but what's
> > the real solution? Is it FTP-client or FTP-server that should take care of
> > the previous DATA port usage? Or even network stack behaviour should be
> > further modified to avoid this collision?
> >
> > Sincerely, Dmitry
> > --
> > Atlantis ISP, System Administrator
> > e-mail:  dmitry at atlantis.dp.ua
> > nic-hdl: LYNX-RIPE
> 
> Sounds like something that should be dealt with on the server's end.  Some
> of the changes we've made in 5.x might fix the problem, but I don't think
> anyone has looked into that specific case.

A port should not be reused this fast.  Maybe the randomness isn't
so random after all and choses the same port over again and again?

> A simpler solution might be to use passive mode.  I think that you can set
> that somewhere in the install options.

Unless he does a full cycle of all available ports there shouldn't be
a collision.

-- 
Andre


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