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Date:      Thu, 29 Feb 1996 11:31:52 -0600 (CST)
From:      Joe Greco <jgreco@brasil.moneng.mei.com>
To:        phk@critter.tfs.com (Poul-Henning Kamp)
Cc:        stable@freebsd.org, current@freebsd.org
Subject:   Re: IPFW (was: Re: -stable hangs at boot)
Message-ID:  <199602291731.LAA04770@brasil.moneng.mei.com>
In-Reply-To: <2612.825584015@critter.tfs.com> from "Poul-Henning Kamp" at Feb 29, 96 09:53:35 am

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> > Technically, one might want to place it's much-less-often-considered brother
> > in the firewall too...  the one that prevents OUTgoing packets that do NOT
> > have a 13.0.0.0 address...
> > 
> > (no I don't do this either but I should).
> 
> And if you're on a lousy ISP, also a filter to block all of the "private"
> networks, 192.168.x.x and so on, (RFC 1596 ?)

RFC1597:

	10.0.0.0        -   10.255.255.255
	172.16.0.0      -   172.31.255.255
	192.168.0.0     -   192.168.255.255

That's a real good point, actually.  Also 127.*, I would think...

(actually, some non-lousy ISP's assign space out of this address range as it
serves as a very "gross" firewall.  And even if you don't, your customers
might use it as described in 1597 and have a misconfigured router that
doesn't prevent outbound packets.  This implies you want to stop traffic in
BOTH directions).

Gosh, this gets complex quickly :-)

... Joe

-------------------------------------------------------------------------------
Joe Greco - Systems Administrator			      jgreco@ns.sol.net
Solaria Public Access UNIX - Milwaukee, WI			   414/546-7968



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