Date: Tue, 4 Jul 2000 22:57:40 -0400 (EDT) From: Brian Dean <bsd@bsdhome.com> To: Doug Barton <DougB@gorean.org> Cc: Greg Lehey <grog@lemis.com>, Samuel Tardieu <sam@inf.enst.fr>, current@FreeBSD.ORG Subject: Re: DHCP does not honor default router? Message-ID: <Pine.BSF.4.21.0007042240200.274-100000@vger.bsdhome.com> In-Reply-To: <3962845C.F195E50D@gorean.org>
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On Tue, 4 Jul 2000, Doug Barton wrote:
> I updated my dhclient script to handle this case, since it
> happens on the roadrunner network as well. I can send you the patch
> if you want, but I have a lot of other hacks in my script so it
> might be confusing. Starting right around line 106 of the default
> script, I have:
A hook is already provided for this kind of thing. You can create a
separate program called /etc/dhclient-exit-hooks, which get run at
various times by dhclient-script. Since /etc/dhclient-exit-hooks is
sourced by /sbin/dhclient-script, you have access to all of its
internal variables, such as '$reason', '$old_ip_address',
'$new_ip_address', etc.
Thus, you don't have to maintain a separate /sbin/dhclient-script like
you do now.
Also, if you run a firewall, you should re-instantiate your rules with
the new IP address here as well. Mine (which is still evolving) looks
something like this:
------------------------------------------------------------
#!/bin/sh
#
# File: /etc/dhclient-exit-hooks
#
# redirect to syslog
logger="/usr/bin/logger -t dhclient-exit-hooks -i"
checkit ( ) {
/bin/echo "REASON=$reason OLDIP=$old_ip_address NEWIP=$new_ip_address"
if [ -z "$old_ip_address" ] || [ -z "$new_ip_address" ]; then
/bin/echo "old and/or new is empty"
elif [ "$old_ip_address" != "$new_ip_address" ]; then
/bin/echo "flushing ARP tables"
/usr/sbin/arp -d -a
/bin/echo "re-establishing firewall rules"
. /etc/rc.firewall.local
fi
}
checkit | $logger
------------------------------------------------------------
I notice you also flush the routing table. Is that necessary - it
appears that dhclient-script does this when it's needed?
I found this exit hook feature by looking at the source for
dhclient-script, but, oddly enough, it is even documented in the man
page.
-Brian
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