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Date:      Wed, 26 Sep 2001 18:48:42 -0500
From:      David Kelly <dkelly@hiwaay.net>
To:        Mike Porter <mupi@mknet.org>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: dhcp & cable, @home (help me fight the MS monopoly)
Message-ID:  <20010926184842.A23164@grumpy.dyndns.org>
In-Reply-To: <200109262029.f8QKTQH00642@c1828785-a.saltlk1.ut.home.com>; from mupi@mknet.org on Wed, Sep 26, 2001 at 02:29:25PM -0600
References:  <3.0.5.32.20010926000700.007ad100@widomaker.com> <200109261325.f8QDPe922234@c1828785-a.saltlk1.ut.home.com> <20010926113441.B12931@acadia.ne.mediaone.net> <200109262029.f8QKTQH00642@c1828785-a.saltlk1.ut.home.com>

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On Wed, Sep 26, 2001 at 02:29:25PM -0600, Mike Porter wrote:
> 
> The problem is that the only times my IP has changed, it has gone from a 
> 24.x.x.x family to a 65.x.x.x family and back, which invalidates the 
> anti-spoofing rules, since those operate on the 24.x.x.255 and 24.x.x.0 
> addresses if I am in a 24-family IP, but on 65.x.x.255 and .0 for the 
> 65-family IP's.  This means that the entire ruleset must be rewritten, not 
> just a matter of flushing the tables and refreshing my own personal IP.  I 
> suppose if I was really ambitious, it would be possible to write some perl or 
> sed or awk that would strip the first three octets from my ifconfig data, and 
> then supply a 255 and a 0, and restructure some of the other rules as well.  
> And as previously noted, that could be tied to dhclient-exit-hooks.  But my 
> wife would object to the time spent.

Ain't hard. Already been posted here in this thread. Here is how I do
it, admittantly with ipfw and not ipf:

	# look for the line with netmask, then awk my IP address
	ip=$(/sbin/ifconfig ${nic} | grep netmask | awk '{print $2}')

Is a bit harder to strip the bytes out of the address one at a time.

> 
> BTW, to reset your firewall, I think all you have to do, if you are using the 
> default ipfw setup, is have dhclient-exit-hooks run /etc/rc.firewall restart. 

There is a dynamic DNS feature in the latest ISC DHCP stuff but I'm not
sure how it hooks in.

Yes, you could link rc.firewall to dhclient-exit-hooks but
dhclient-exit-hooks sometimes runs 4 times for each lease renewal. This
is not what anyone really wants to do.

-- 
David Kelly N4HHE, dkelly@hiwaay.net
=====================================================================
The human mind ordinarily operates at only ten percent of its
capacity -- the rest is overhead for the operating system.

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