Subject: default route deleted incorrectly with dhclient
To: None <tech-net@netbsd.org>
From: Steven M. Bellovin <smb@cs.columbia.edu>
List: tech-net
Date: 07/19/2006 22:51:29
A while back, I posted a note about the wrong default route being deleted
with dhclient. Specifically, if I have a lease on int0, suspend my
laptop, and get a lease on int1 instead, when int0's lease expires the
default route -- via int1 -- will be deleted.
Here's a patch that's currently in my /etc/dhclient-enter-hooks, but could
(or should) go into /sbin/dhclient-script instead. How does it look? (It
would replace the current text of the delete_old_routes() function.)
delete_default() {
route show -inet | sed 1,4d | \
while read dest gw flags
do
if [ "$dest" = default -a "$gw" = "$1" ]
then
route delete -inet $dest $gw
echo route delete -inet $dest $gw >&2
fi
done
}
delete_old_routes() {
for router in $old_routers; do
delete_default "$router"
done >/dev/null 2>&1
set -- $old_static_routes
while [ $# -gt 1 ]; do
route delete $1 $2
shift; shift
done
arp -n -a | sed -n -e 's/^.*(\(.*\)) at .*$/arp -n -d \1/p' | sh
}
--Steven M. Bellovin, http://www.cs.columbia.edu/~smb