[arin-ppml] The role of NAT in IPv6
Michael Richardson
mcr at sandelman.ca
Sun Apr 18 12:39:06 EDT 2010
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>>>>> "michael" == michael dillon <michael.dillon at bt.com> writes:
>> I deployed IPv4 NAT back in 1996 (or earlier, I forget) in a
>> production environment. The way I did it - and the ONLY way that
>> ANYONE could do it at that time - was by applying a very large,
>> convoluted set of patches to the FreeBSD 3 kernel and compiling
>> the nat daemon.
michael> At that time I was running TIS firewalls toolkit on a
michael> FreeBSD 2 system. It was not NAT, but to the outside world,
michael> the application layer proxies did present multiple machines
michael> inside the network on a single IP address, just like NAT
michael> did. And an external machine could not pass packets to an
michael> internal one, unless a proxy was specifically configured to
michael> allow it, just like on a NAT box.
Between 1994 and 1996 (when I left), I shipped hundreds of Milkyway
Blackhole firewalls. In their default configuration, they did
transparent proxy via application layer firewalling, which effectively
is NAPT, but it occurs at layer-5+.
We had a configuration we called "Whitehole", which essentially was
application layer firewall, but it revealed the internal IPs. Or more
precisely, it was 1:1 NAT, with an identity function for the mapping.
(All of the protection, none of the calories...)
Of course, you could mix and match what you wanted, on a per-rule basis.
My opinion is that it was all a mistake from a security point of view
- --- what we (the firewall industry) did was permit microsoft to ship
win95 with major bugs, many of which are still not fixed. (Many are
considered "features")
A significant number of (technical) people have never actually been on
the "bare" Internet... You can see them at ARIN, NANOG or IETF meetings
- --- those are the people re-installing their laptop system in the
"terminal room".
NAPT has been a major negative --- it causes networks to be too
complex to manage, and many PHBs can't understand it at all.
- --
] He who is tired of Weird Al is tired of life! | firewalls [
] Michael Richardson, Sandelman Software Works, Ottawa, ON |net architect[
] mcr at sandelman.ottawa.on.ca http://www.sandelman.ottawa.on.ca/ |device driver[
Kyoto Plus: watch the video <http://www.youtube.com/watch?v=kzx1ycLXQSE>
then sign the petition.
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