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Date:      Wed, 16 Jun 2004 07:20:32 -0400
From:      Bill Moran <wmoran@potentialtech.com>
To:        Kevin Curran <kevin@curranfamilynet.net>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: Are 4 IPFW rules enough?
Message-ID:  <20040616072032.0a5ee617.wmoran@potentialtech.com>
In-Reply-To: <1087261927.5494.11.camel@tower>
References:  <1087261927.5494.11.camel@tower>

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Kevin Curran <kevin@curranfamilynet.net> wrote:

> I have a cable modem and I'm using 4.9 as a NAT router for my home
> network.  I have 4 rules in my ipfw config.  The first enables NAT and
> the last is 65000 allow any to any.
> 
> In between I ha 2 rules to deny access to ports 53 and 110 on the
> Internet side.  That's all.  
> 
> Here's my thinking: I use inetd.conf to enable only the services I want,
> therefore the ports on which those services are listening I would want
> open.  The two other ports I want to filter on the WAN side are filtered
> by the rules above.  All the other ports are closed, anyway, so why
> spend time debugging an elaborate rule set?

Check the output of "sockstat -4" to ensure that you don't have anything running
that you aren't aware of ... syslogd is a typical culpret.  You'll probably
have to add syslogd_flags="-ss" to /etc/rc.conf

Otherwise, you're probably good, execpt that there are some spoofing techniques
that may be able to get around such a ruleset.  That's beyond my expertise,
however.

-- 
Bill Moran
Potential Technologies
http://www.potentialtech.com



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