nanog mailing list archives
Re: Security gain from NAT (was: Re: Cool IPv6 Stuff)
From: Owen DeLong <owen () delong com>
Date: Mon, 4 Jun 2007 11:47:15 -0700
On Jun 4, 2007, at 11:32 AM, Jim Shankland wrote:
Owen DeLong <owen () delong com> writes:There's no security gain from not having real IPs on machines. Any belief that there is results from a lack of understanding.This is one of those assertions that gets repeated so often people are liable to start believing it's true :-).
Maybe because it _IS_ true.
*No* security gain? No protection against port scans from Bucharest? No protection for a machine that is used in practice only on the local, office LAN? Or to access a single, corporate Web site?
Correct. There's nothing you get from NAT in that respect that you do not get from good stateful inspection firewalls. NONE whatsoever.
Shall I do the experiment again where I set up a Linux box at an RFC1918 address, behind a NAT device, publish the root password of the Linux box and its RFC1918 address, and invite all comers to prove me wrong by showing evidence that they've successfully logged into the Linux box? When I last did this, I got a handful of emails, some quite snide, suggesting I was some combination of ignorant, stupid, and reckless; the Linux box for some reason remained unmolested.
That doesn't prove that NAT had anything to do with the security. NAT implies stateful inspection. I could conduct the exact same experiment with a Linux box behind a stateful inspection firewall with legitimate addresses and achieve the exact same result. NAT did nothing for you. Stateful inspection is where you got your security. I'm so tired of people who fail to understand that NAT hasnothing to do with security, because they forget that stateful inspection
is required in order to make NAT work. However, NAT is not required for stateful inspection to work. Owen
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Current thread:
- Re: Cool IPv6 Stuff, (continued)
- Re: Cool IPv6 Stuff Adrian Chadd (Jun 04)
- Re: Cool IPv6 Stuff Donald Stahl (Jun 04)
- Re: Cool IPv6 Stuff Adrian Chadd (Jun 04)
- Re: Cool IPv6 Stuff Iljitsch van Beijnum (Jun 06)
- Re: Cool IPv6 Stuff Joel Jaeggli (Jun 04)
- Re: Cool IPv6 Stuff Owen DeLong (Jun 04)
- Security gain from NAT (was: Re: Cool IPv6 Stuff) Jim Shankland (Jun 04)
- Re: Security gain from NAT (was: Re: Cool IPv6 Stuff) Joe Abley (Jun 04)
- Re: Security gain from NAT Sam Stickland (Jun 04)
- RE: Security gain from NAT Howard C. Berkowitz (Jun 04)
- Re: Security gain from NAT (was: Re: Cool IPv6 Stuff) Owen DeLong (Jun 04)
- Re: Security gain from NAT (was: Re: Cool IPv6 Stuff) Colm MacCarthaigh (Jun 04)
- Re: Security gain from NAT (was: Re: Cool IPv6 Stuff) Matthew Palmer (Jun 04)
- Re: Security gain from NAT (was: Re: Cool IPv6 Stuff) Donald Stahl (Jun 04)
- Re: Security gain from NAT Jason Lewis (Jun 04)
- Re: Security gain from NAT Daniel Senie (Jun 04)
- Re: Security gain from NAT Steven M. Bellovin (Jun 05)
- RE: Security gain from NAT (was: Re: Cool IPv6 Stuff) David Schwartz (Jun 04)
- RE: Security gain from NAT (was: Re: Cool IPv6 Stuff) Donald Stahl (Jun 04)
- Re: Security gain from NAT (was: Re: Cool IPv6 Stuff) Owen DeLong (Jun 04)
- RE: Security gain from NAT (was: Re: Cool IPv6 Stuff) David Schwartz (Jun 04)