Subject: (NAT) headaches with NAT and patents.

From: Darren Reed <[email-masked]>
Date: Thu, 21 Sep 2000 23:56:47 +1100 (EST)

In recent days, someone has made me aware of a patent by Cisco on NAT,
#5793763.  Someone pointed me to a NATwg web page which referenced IBM
and mentioned they had a patent which was filed before Cisco's.  On top
of this, I've had someone contact me and mention that they did a NAT
implementation in a time frame which would pre-date the filing dates
of both patents.  Is this something which is worth following up with
further, for details, so that the IETF work can be considered "patent
free" ?

btw, having read both the IBM and Cisco patent, is it just me or do
both patents only make a claim for "half" of the process - that of
`restoring' the original destination IP address ?

Darren
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From: Darren Reed <[email-masked]>
Date: Fri, 22 Sep 2000 05:58:01 +1100 (EST)

In some email I received from Paul Francis, sie wrote:
[Charset iso-8859-1 unsupported, filtering to ASCII...]
> What are the filing dates?  (for that matter, do you have a pointer to the
> patent?)

The IBM patent is December 1994 - the URL for this group is
http://www.ietf.org/ietf/IPR/NAT-VRRP-IBM

The Cisco patent was filed November 1995 - number 5793763.

> I gave the first public talk of NAT at the Vancouver IETF (summer 1990), and
> published it in sigcomm CCR around '91-'92.  That publication talked about
> various things including dns tricks, but unfortunately I don't think it
> included port translation.

Do you have pointers to these papers, online, as URLs ?

Darren
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