IPv6 uptake (was: The Reg does 240/4)

Sat Feb 17 03:10:34 UTC 2024

It appears that William Herrin <bill at herrin.us> said:
>Now suppose I have a firewall at 199.33.225.1 with an internal network
>of 192.168.55.0/24. Inside the network on 192.168.55.4 I have a switch
>that accepts telnet connections with a user/password of admin/admin.
>On the firewall, I program it to do NAT translation from
>192.168.55.0/24 to 199.33.225.1 when sending packets outbound, which
>also has the effect of disallowing inbound packets to 192.168.55.0/24
>which are not part of an established connection.

Or you set up port forwarding for some other device but you mistype the
internal address an forward it to the switch.  Or the switch helpfully
uses UPNP to do its own port forwarding and you forget to turn it off.

If you configure your firewall wrong, bad things will happen.  I have both
IPv6 and NAT IPv4 on my network here and I haven't found it particularly
hard to get the config correct for IPv6.

Normally the ISP will give you an IPv6 /56 or larger so you can have
multiple segments behind the router each with a /64 and different
policies for each segment.