Well... that's a mouthful of questions ;-).
I'm not quite ready to post my email address, but if you want to post yours here, I might (might!) reply. I generally tend to prefer keeping these things in the public forums, though, because it benefits everyone the most when we can discuss, and have our ideas challenged, etc...
To understand why FreeBSD is a true Unix, you have to look at the history of BSD, and Unix itself (
Essentially, when the University of California at Berkeley wanted to release an open version of BSD Unix, there was a fight with AT&T, who had helped develop BSD. It was finally resolved by stripping out the AT&T proprietary code. Thus, FreeBSD is the original Berkeley Unix, with a few areas replaced by additional code from--the University of California at Berkeley. Pretty darn authentic, if you ask me.
Also, you must remember that this was done right around the time that Linus Torvalds was just beginning to develop Linux. Thus a mature OS was released as open source while Linux was just a development kernel and some utilities.
FreeBSD was released with a completely different license from Linux. The Linux GPL specifically forbids anyone from using source code in other proprietary products. The BSD open license allows you to do anything you want with the source code, up to, and including making any piece of code a part of your proprietary product. Many GNU supporters claim that this approach harms the whole open source movement, allowing businesses to "steal" the work of BSD programmers. Well, the BSD programmers appear to be quite comfortable with this, and BSD code has been used in many interesting places, including quite a bit of networking components of Windows 2000/XP. (This was admitted by Microsoft, as is their legal duty according to the BSD license-- you have to at least give BSD credit for inclusion of the code) Also, the new Apple OS X owes quite a lot of it's core to FreeBSD. Also, many of these companies see the benefit of contributing money and research efforts to the FreeBSD project.
This whole process hasn't seemed to harm the development of FreeBSD in the least; it's development team is thriving. I suspect that quite a lot of modern networking and OS code owes some of its success to FreeBSD. The FreeBSD network stack has especially been the subject of serious study, since apparently no one has been able to significantly improve on it's core algorithms in years. (Disclaimer: I am not an expert in kernel hacking, so don't take my word here as absolute)
POSIX compliance is not the same thing as Unix. Even Windows NT was supposed to be POSIX-compliant (I'm sure there's room for debate here ;-)).
So... that's the historical (or hysterical) context of all this.
Slackware and Debian are both "do-it-yourself" type Linux systems. Slackware development was actually pretty closely aligned with FreeBSD for awhile, and thus it works very similarly. Slackware is probably the closest Linux comes to a BSD Unix. Thus my two favorite OS's are FreeBSD, and Slackware. I still give FreeBSD slightly better marks as a server, though. I have had absolutely NO problems with the FreeBSD ever, as a server.
As to your question about ipfilter/ipchains, I can't really comment. I have not really had to use either, and my firewall needs are fairly modest, so I haven't really spent much time exploring the alternatives. I use
ipfw, though, which is the standard NAT firewall for FreeBSD, and it works as smoothly as I could hope. If you have any more questions about advanced BSD firewalling, ask in the FreeBSD forum, and member "aaxvp" (who is a good friend of mine) will be able to help you more. -------------------
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