From: Eric Garver <eric@garver.life>
To: Florian Westphal <fw@strlen.de>
Cc: netfilter-devel@vger.kernel.org, Phil Sutter <phil@nwl.cc>
Subject: Re: [PATCH nf] netfilter: nat: force port remap to prevent shadowing well-known ports
Date: Tue, 30 Nov 2021 09:34:41 -0500 [thread overview]
Message-ID: <YaY2gbreectkdeX3@egarver.remote.csb> (raw)
In-Reply-To: <20211129220254.GA17540@breakpoint.cc>
On Mon, Nov 29, 2021 at 11:02:54PM +0100, Florian Westphal wrote:
> Eric Garver <eric@garver.life> wrote:
> > On Mon, Nov 29, 2021 at 03:42:18PM +0100, Florian Westphal wrote:
> > > If destination port is above 32k and source port below 16k
> > > assume this might cause 'port shadowing' where a 'new' inbound
> > > connection matches an existing one, e.g.
> >
> > How did you arrive at 16k?
>
> I had to pick some number. 1k is too low since some administrative
> portals (or openvpn for that matter) are on ports above that.
>
> I wanted to pick something that would not kick in for most cases.
> 16k just seemed like a good compromise, thats all.
Understood. I don't have a real reason to choose anything else.
That being said, there are more things registered in the > 16k range
than I realized.
next prev parent reply other threads:[~2021-11-30 14:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-29 14:42 [PATCH nf] netfilter: nat: force port remap to prevent shadowing well-known ports Florian Westphal
2021-11-29 20:22 ` Eric Garver
2021-11-29 22:02 ` Florian Westphal
2021-11-30 14:34 ` Eric Garver [this message]
2021-12-08 0:28 ` Pablo Neira Ayuso
2021-12-08 10:47 ` Florian Westphal
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