Re: IPv4 flag day

On Thu, Jun 18, 2026 at 10:02 AM Gary Sparkes
<[email protected]> wrote:
> I mean, it's precisely why technology like STUN/TURN/ICE exist.
>As to your ask, with two firewalls, inbound default deny, accept related/established
>only (So, standard SMB/residential CPE setup), and one having NAT and the other not having NAT, I can.....
>
> Drop a box (raspberry pi, for example) inside the network and VPN into it without having to establish a reverse tunnel first.

I'm sorry, Gary, you're going to establish a VPN to the Pi behind the
NAT _without_ the Pi initiating outbound packets and establsihing
connection state in the 1:many NAT firewall first? I don't think so.
You're going to at least send a set of packets from the Pi to
establish state in the NAT firewall. That's how STUN works. TURN flat
out defies your conditions: it fully establishes the connection for a
reverse tunnel via the external TURN server.

And that same set of packets establishes the same state in the non-NAT
firewall. You haven't demonstrated your claim that the NAT version is
-more- vulnerable to the attack.

Meanwhile, I don't claim that the NAT firewall makes a network less
vulnerable to this sort of physical infiltration. Merely that there
are other common attacks to which it is less vulnerable, even when
misconfigured.

Regards,
Bill Herrin

-- 
For hire. https://bill.herrin.us/resume/
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