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From: Darren Reed <avalon@coombs.anu.edu.au>
Subject: Re: IPFW !IP#
To: adam@veda.is (Adam David)
Date: Wed, 18 Sep 1996 16:21:01 +1000 (EST)
Cc: freebsd-hackers@freebsd.org
In-Reply-To: <199609180251.CAA11480@veda.is> from "Adam David" at Sep 18, 96 02:51:28 am
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In some mail from Adam David, sie said:
> 
> I can implement exclusion of a block of IP addresses at low execution cost.
> Does anyone dislike this idea? Which flags mask would be more preferred for
> this purpose, 0xc000 or 0x0003? (does anything already use 0x0003?)
> Are the unused flags perhaps reserved for something more useful than this?
> 
> # ipfw add deny all from !${my_network}:${my_netmask} to any out via ${gate_if}
> # ipfw add deny all from any to !${my_network}:${my_netmask} in via ${gate_if}
> 
> This set of 2 rules would otherwise take 48 rules to enforce for a class C
> network with a single domain gateway, for instance.

This is just rule writing.

HOw about:

# ipfw add pass all from ${my_network}:${my_netmask} to any out via ${gate_if}
# ipfw add pass all from any to ${my_network}:${my_netmask} in via ${gate_if}
# ipfw add deny all from any to any out via ${gate_if}
# ipfw add deny all from any to any in via ${gate_if}

Darren