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Date:      Sun, 1 Jul 2001 23:00:16 +0200
From:      "Alfatrion" <alfatrion@cybertron.tmfweb.nl>
To:        "Fernando Gleiser" <fgleiser@cactus.fi.uba.ar>, "Louis LeBlanc" <leblanc+freebsd@acadia.ne.mediaone.net>
Cc:        <freebsd-questions@FreeBSD.ORG>
Subject:   Re: Firewall:  ipfw? ipfilter? dhcp lease?
Message-ID:  <002e01c10271$21fc08d0$231fa8c0@dekruijff.nl>
References:  <20010701161952.A16304-100000@cactus.fi.uba.ar>

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> > Hey all.  FreeBSD newbie/convert in training here.
> > Couple questions regarding firewalls.
> >
> > First some background on what I am doing now (meaning I have enough
> > knowledge to get by on my current setup)
> >
> > I am currently using RH6.2 with ipchains for my firewall.  I am
> > blocking and allowing different ports from all or just a subnet (all
> > open from my work subnet, most closed from all else, that kind of
> > thing).  I also have it set up with dhcpcd (pump doesn't do it for me)
> > so that when I get a new dhcp lease, the firewall is reinitialized by
> > executing the rc.firewall script with each dhcp lease.
> >
> > Anyway, I have just finally gotten around to getting a new (for me)
> > machine at home to run FreeBSD on, and I want to set that up as my
> > front end machine (hooked directly to the cable modem, running the
> > firewall, masquerading, maybe doing nat, etc.), but I also want to
> > make sure the firewall will stay up with the current dhcp lease.
> >
> > Anyway, I have been reading about firewalls on the list for a while,
> > and am wondering about the differences between using ipfilter and
> > ipfw.  I take it FreeBSD is not using ipchains, so I won't go there.
> >
> > I assume there is some flexibility/security/simplicity tradeoff
> > between the two?  Seems logical to me if so.  Is one easier to
> > configure?  What about resource requirements? (not that that would be
> > an issue, but I'm curious.)
> >
> > I am well aware that there are books available on the subject, a
> > couple are plugged right in the /etc/rc.firewall script, but I want to
> > make a decision on the approach first, and pick the book or books, web
> > resources, etc. that most apply to my decision (I already have plenty
> > of books that "don't apply")
> >
> > Also, are there any online tools to help set up such a firewall?  I
> > have been using an ipchains firewall I generated with Rob Ziegler's
> > excellent Linux Firewall Design Tool at
> > http://www.linux-firewall-tools.com/linux/firewall/index.html
> > And yes, it is excellent!  Unfortunately, I don't think he has gotten
> > too much into the FreeBSD world.  Maybe I'll scout his site again
> > later, or better yet, email him.
> >
> > BTW, some of you may have noticed that I had asked about 5.0-CURRENT
> > recently, but I will be running 4.3-STABLE on this machine.  I am
> > (or was) putting -CURRENT on an extra desktop I have 'absconded' at
> > work for experimentation.  Just an FYI.
> >
> > Any and all useful commentary on the subject is more than welcome and
> > much appreciated.  I hope I have not strayed too far from list
> > etiquette in terms of being both complete and concise, but please
> > forgive me if I have, and feel free to let me know so I can correct
> > any errant behavior, as I expect to have a lot of questions for the
> > list in the future :).
> >

> Both ipf and ipfw are roughly equivalent, and each one has its strenghts
and
> weaknesses. For me, they are way better (better syntax, better features,
> easier to configure) than IP chains.
>
> I am using IP Filter, because it suits my particular needs better.
> I use IPfilter instead of ipfw because:
>
> 1. compatibility with other OS (solaris, other bsd)
> 2. I like the stateful inspection features of ipf better.
> 3. Rule grouping. You can make the rules tree shaped instead of linear,
>    speeding up the rule matching.
> 4. I prefer ipnat over natd.
>
> On the other hand with ipfw you can:
>
> 1. Use a traffic shaper (dummynet).
> 2. Select where you want to NAT (at the beginning, at the end, somewhere
in
>    between)
>
> You can even use them both at the same time (I use ipf for NAT/filtering
> and ipfw for dummynet).
>
> The ipf howto is at http://www.obfuscation.org/ipf/ipf-howto.txt
> The ipfw howto is at http://www.mostgraveconcern.com/freebsd/ipfw.html
>
> The IP Filter mailing list archives are at http://false.net/ipfilter
>
> My advice is try them both, and pick the one that fits your needs better.
>
> Hope this helps
>

You number three reson is also posible with IPFW
Alex


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