Hello, > I am new to the mailing list and don't know if my question has already > an answer ;-) > It is not a technical question but a question about the use of the words > 'stateful inspection' > > In fact, we are developping a PBX with linux OS and netfilter as a > firewall (using stateful inspection) > I found a patent for Checkpoint (Claim chart US5606668) for the > 'stateful Inspection'.
First of all, I sincerely hope that you are aware that you cannot expect to receive any kind of legally binding advice on a public mailing list run by volunteers of software development. If you need legal information, please contact your legal department. I am sure they are good at dealing with such things, Alcatel being a long-established player in the Telecom markets. That said, I would like to note that patents are claimed on technical procedures, not on words contained therein. However, looking at http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/search-adv.htm&r=80&f=G&l=50&d=FT00&p=2&S1=5,606,668&OS=5,606,668&RS=5,606,668 I cannot even find mention of 'stateful inspection'. So, how did you come to the above finding? BTW, as usual for a technical type like me, the stuff I read in the above patent application reads like a strangely worded techreport on pretty obvious ways to go about things. Berkeley BPF [1] seems to be a good piece of prior art, with first publication of the software (according to its changelog) in January 1992. > Is this mean that using Netfilter with stateful inspection is outlaw or > can I use Netfilter without difficulty ?? For whatever my advice may be worth to you, in my personal opinion, you can use netfilter without difficulty. best regards Patrick [1] See http://www-nrg.ee.lbl.gov/nrg.html, link in the middle of page.
