misunderstanding scale

Timothy Morizot tmorizot at gmail.com
Mon Mar 24 18:46:06 UTC 2014


On Mon, Mar 24, 2014 at 8:25 AM, Joe Greco <jgreco at ns.sol.net> wrote:

> Bill Herrin wrote:
>
> I say this with the utmost respect, but you must understand the
> > principle of defense in depth in order to make competent security
> > decisions for your organization. Smart people disagree on the details
> > but the principle is not only iron clad, it applies to all forms of
> > security, not just IP network security.
>
> The problem here is that what's actually going on is that you're now
> enshrining as a "security" device a hacky, ill-conceived workaround
> for a lack of flexibility/space/etc in IPv4.  NAT was not designed
> to act as a security feature.
>
> If you want more layers of security, put a second firewall into your
> design.  Don't perpetuate horrid IPv4 hacks that were necessary for
> specific reasons into IPv6 where those hacks are no longer needed.
>
With 24 million small businesses in the US alone, that's way too many
> apples.
>

Precisely. Repeat after me. NAT is not a security feature. Period. It
offers no meaningful protection. We've known how to bypass NATs almost from
the moment they were developed.

Defense in depth has nothing to do with NAT. In our enterprise deployment,
it involves two layers of heterogeneous firewalls (protecting multiple
security zones from the internal network and the Internet), IPS/IDS, web
filters, mail filters, and an active CSIRC monitoring, analyzing, and
responding to threats and attacks. If you're an enterprise and don't have
something similar in place, then you have no security defense in depth.

Thanks goodness our Cybersecurity organization actually comprehends real
computer and network security instead of promoting snake oil.

Scott


More information about the NANOG mailing list