nanog mailing list archives

Re: [External] Re: IPv6 uptake


From: Tim Howe <tim.h () bendtel com>
Date: Mon, 19 Feb 2024 10:31:20 -0800

Some responses below.

On Mon, 19 Feb 2024 10:01:06 -0800
William Herrin <bill () herrin us> wrote:

I've never once seen a device
that has v6 support and didn't have a stateful v6 firewall on by
default (if v6 was "on").  

Acknowledged.

So when the user wants to run a home server, their IPv4 options are to
create a TCP or UDP port forward for a single service port or perhaps
create a generic port forward for every port to a single internal
machine. Protocols other than TCP and UDP not supported.

        OK, but I'm not sure what you are getting at by saying this is
TCP and UDP exclusive... I don't know why it would be; what's the
example you think is typically being denied?

They might
also have the option of a "bridge" mode in which only one internal
host is usable and the IPv4 functions of the device are disabled. The
bridge mode is the only "off" setting for the IPv4 firewall.

Correct?

Their IPv6 options *might* include these but also include the option
to turn the IPv6 firewall off. At which point IPv4 is still firewalled
but IPv6 is not and allows all L4 protocols, not just TCP and UDP.

Also correct?

        This isn't how I would characterize any of this, to be honest.
I think what you are trying to say is that a v6 firewall can be "off"
while IPv6 connectivity remains unhindered, but turning "off" an IPv4
firewall means no hosts behind NAT will continue to have connectivity.
The assumption being that a guardrail for someone being really
self-destructive is removed.

        OK.  So someone really wanted connectivity and really wanted to
disable security.  Maybe.
        I still believe that the statement "IPv6 is typically delivered
to "most people" without border security" to be demonstrably false.

-- 
TimH


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