Re: [IPv6] Can We Turn the Global Network into a Firewall Protecting All End Users?

I had thought of doing something where the device could send a profile to the router/DHCP server that says “here’s the ports, dns names, etc.. that I will be using”.

This would then permit only those related bits to flow.

- Jared

> On Apr 24, 2024, at 4:23 PM, Hubert W <hubert.wisniewski@gmail.com> wrote:
> 
> 
> 
> On Wed, Apr 24, 2024, 07:46 Mark Andrews <marka@isc.org> wrote:
> 
> 
> > On 23 Apr 2024, at 16:51, Hubert W <hubert.wisniewski@gmail.com> wrote:
> > 
> > Dear WG,
> > 
> > 
> > I woke up with one idea and I would like to challenge it. 
> > In IPv6, every device receives a routable address. To protect endpoints effectively, we require firewalls to filter unwanted traffic. 
> 
> Apart from packet volume this is a false assertion.  No device should require a firewall.
> 
> > But what if we could stop such traffic at the source? Could this approach convince more people toward adopting IPv6?
> > 
> > According to RFC 7381: “In a /48 assignment, typical for a site, there are then still 65,535 /64 blocks.” and “All user access networks should be a /64.”
> 
> /64 is typical not required.
> 
> > Can we use then bit 63 to convey a message: “I don’t want any incoming traffic initiated towards me!!!”? Of course a response would be accepted.
> > 
> > We could divide the /64 allocations into two groups: one for servers, and these accept incoming traffic (bit 63 = 0):
> > 
> > for example 2001:0db8:0000:0000::/64
> > 
> > And the second group: endpoints, these never accept incoming traffic (bit 63 = 1):
> > 
> > for example 2001:0db8:0000:0001::/64
> > 
> > We only need all systems to understand the message. If a router or firewall sees such a packet, then drops it. 
> > Every TCP packet with flag SYN, where destination address (IPv6) has bit 63 equal 1, must be dropped.
> 
> All the world is not TCP.  Additionally for TCP the filtering device would need to track state and that implies symmetric routing.
> 
> > Would it be theoretically possible?
> 
> No.
> 
> > Best regards
> > 
> > Hubert Wisniewski
> > 
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> -- 
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742              INTERNET: marka@isc.org
> I think there would be no issue with asymmetric traffic if we only check SYN flag, but I understand that is not a good idea. Thank you for your opinion. 
> 
> Hubert Wisniewski 
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