OpenBSD/ (maybe FreeBSD) Firewall/Router/DNS

[Micheal Patterson]

----- Original Message ----- 
From: "Bryan Cassidy" <b_cassidy at bellsouth.net>
To: <freebsd-questions at freebsd.org>
Sent: Tuesday, May 11, 2004 12:20 AM
Subject: OpenBSD/ (maybe FreeBSD) Firewall/Router/DNS


> Hello. I am currently running FreeBSD 4.9-RELEASE p-7. I am pretty
comfortable with FreeBSD for the most part and really enjoy using it on a
day to day basis. This is my thoughts. I have an older NEC PC that I would
like to put to some use. First off I don't know if I need any 'extra'
hardware. I have now 1 DSL modem (dhcp - could get static, is it worth
getting?), 3 NICs, and 2 cables to connect the ethernet cards. I have just
been reading up on Firewalls on FreeBSD using ipfw. I would basically like
to do the following. I want to install OpenBSD 3.5 or Possibly one of the
FreeBSD 4.x, 5.x, 4-stable, current or whatever. Which would you all
recommend using in this situation? I want to continue to use my nice newer,
much faster computer to do all configurations to the system, updates,
installing software, running apache, configuring firewall, etc. etc. etc.
via ssh (good choice?) to the other/older box. Would really appreciate some
insight on this topic. Networking/Security is becoming very interesting to
my. Thanks. Don't forget, do I need any 'extra' hardware?
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I can't speak for anyone else but myself, but here's my opinion on this.

If you have an older box, you'll need 2 nics. One (external / serial
interface) to the dsl modem (crossover cable), one to the lan side. If this
is also to a PC, you'll need another crossover cable. If the old NEC is a
486 with at least 32 mb ram, that should be all you'll need hardware wise as
long a it's got a couple of gig for drive space. If you want to enable full
firewall logging, you'll need more disk space for that of course. What I'd
recommend doing in your situation, is the same as I have here at home. Have
the bsd box (I prefer freebsd myself) connect to your provider and pull the
ip on the serial interface, then assign a private ip to the internal nic and
to the systems behind it on the lan. Then on the bsd box, enable nat and the
first rule of your firewall will be a divert rule to pass everything to NAT.

For more info on this and it's configuration, check out


http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/book.html

or

http://www.freebsddiary.org/ipfw.php

If you're still wanting more info, then I'd recommend a google search for
freebsd natd and / or freebsd ipfw to get a lot of good and useful info.

Hope it helps.
--

Micheal Patterson
TSG Network Administration
405-917-0600

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