From: Eric Ziegast <ziegast@zee.im.gte.com>
To: nanog@merit.edu; namedroppers@internic.net
Subject: Re: The SWAMP
Date: Monday, September 09, 1996 7:47 PM
In cron:
# pick a random time once a week
31 10 * * 4 /usr/sbin/update-root
# some other time during the week
23 20 * * 6 /usr/sbin/named.restartThe shell script (off the top of my head):
#!/bin/sh
tmp=/tmp/rs$$
trap "rm -f $tmp" 1 2 3 14 15
chdir /etc/namedb
ncftp -a -d 600 -g 5 ftp.root-servers.net:/named.root
if [ ! -r named.root ]; then
Mail -s "Could not get root nameserver list" hostmaster
fi
diff root.cache root-servers > $tmp
if [ -s $tmp ]; then
mv named.root root.cache # fails if couldn't download
Mail -s "Root server update" hostmaster < $tmp
fi
rm -f $tmp
I don't like "automatic" updates. Sure it is convenient, but for something
as mission-critical as name service, I would hesitate to automatically
trust whatever happens to be at ftp.root-servers.net:/named.root on any
given day. I would want to review it first. Plus, on most BSDish systems
/etc/crontab is world readable by default. A cracker would know the exact
time to attempt to hijack the FTP session and insert:
. IN NS you.got.hacked.net.
you.got.hacked.net. IN A 10.1.2.3
-BD