Date: Wed, 11 Oct 2000 02:05:59 +0200 From: Gerhard Sittig <Gerhard.Sittig@gmx.net> To: freebsd-stable@FreeBSD.ORG Subject: Re: ipf vs. ipfw ? Message-ID: <20001011020559.Y31338@speedy.gsinet> In-Reply-To: <14819.8982.61823.868907@onceler.kciLink.com>; from khera@kciLink.com on Tue, Oct 10, 2000 at 10:09:26AM -0400 References: <20001008224359.R31338@speedy.gsinet> <Pine.BSF.4.21.0010082235080.3908-100000@turtle.looksharp.net> <20001009193445.T31338@speedy.gsinet> <14819.8982.61823.868907@onceler.kciLink.com>
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On Tue, Oct 10, 2000 at 10:09 -0400, Vivek Khera wrote:
> >>>>> "GS" == Gerhard Sittig <Gerhard.Sittig@gmx.net> writes:
>
> GS> same mechanism -- just with ipfw behind the pipe! And these
> GS> substitutions maybe could get nested if needed like this:
>
> GS> REPEAT S1 $SRC : REPEAT S2 $DEST : pass ... from S1 to S2 ...
>
> GS> if implemented in some intelligent way. Has someone gotten
> GS> behind the stage of thinking about this and actually started
> GS> planning or implementing it? I would be interested in different
> GS> thoughts.
>
> ipfw lets you pre-process a file using any arbitrary pre-processor.
> It recommends cpp or m4, but who's to stop you from using perl? Just
> make your FW rule file be a perl program and run it thusly:
>
> ipfw -p /usr/bin/perl firewall.perl
>
> and you're set.
That's exactly what I have now (150 lines of Perl code doing
loops and grouping and substitutions, etc). But I have to admin
that I don't use ipfw -- I don't want to learn another syntax,
and I don't miss the dummy bandwidth limiter. That's why I stick
with ipf (plus because I have machines around not running
FreeBSD).
> Just make sure that the output of your firewall.perl program is
> a valid set of firewall rules. I guess the only trick would be
> figuring out how to pass flags to your program.
Not at all with the hooks I applied to /etc/rc.network. :) And
one could even drive it to insanity with stacking shell code
(here document) and cpp and perl and whatever upon each other. :>
In case there's popular demand, I could post the 4KB script.
It's not tied to any filter language and not even to substituting
filter rules. Although it's just a hack. Anyone could do better
on their own, I guess.
virtually yours 82D1 9B9C 01DC 4FB4 D7B4 61BE 3F49 4F77 72DE DA76
Gerhard Sittig true | mail -s "get gpg key" Gerhard.Sittig@gmx.net
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