North American Network Operators Group

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Re: Security gain from NAT (was: Re: Cool IPv6 Stuff)

  • From: Matthew Palmer
  • Date: Mon Jun 04 18:24:33 2007

On Mon, Jun 04, 2007 at 12:20:38PM -0700, Jim Shankland wrote:
> But NAT *requires* stateful inspection; and the many-to-one, port
> translating NAT in common use all but requires affirmative steps
> to be taken to relay inbound connections to a designated, internal
> host -- the default ends up being to drop them.  All this can be
> done without NAT, but with NAT you get it "for free".

Except for the costs of NAT, which it could be argued are, long term, higher
than the costs of just setting up a firewall properly.  There's also no
reason why the default policy on a firewall, out of the box, cannot be "no
inbound".  It's not beyond the realm of possibility that the UI for the
firewall device could be such that it was hard-to-impossible to turn off the
"no inbound by default" rule.

> I can't pass over Valdis's statement that a "good properly configured
> stateful firewall should be doing [this] already" without noting
> that on today's Internet, the gap between "should" and "is" is
> often large.

"In theory, there is no difference between theory and practice.  In
practice, there is."

"There should be no difference between 'should' and 'is'.  However, there

- Matt

I have always wished that my computer would be as easy to use as my
telephone. My wish has come true. I no longer know how to use my telephone.
		-- Bjarne Stroustrup