8. Maintenance
Keeping it working.
There is one maintenance task you have to do on nameds, other than
keeping them running. That's keeping the root.hints file
updated. The easiest way is using dig. First run dig with
no arguments you will get the root.hints according to your own
server. Then ask one of the listed root servers with dig
@rootserver. You will note that the output looks terribly like a
root.hints file. Save it to a file (dig @e.root-servers.net
. ns >root.hints.new) and replace the old root.hints with it.
Remember to reload named after replacing the cache file.
Al Longyear sent me this script that can be run automatically to
update root.hints. Install a crontab entry to run it once a
month and forget it. The script assumes you have mail working and
that the mail-alias `hostmaster' is defined. You must hack it to suit
your setup.
#!/bin/sh
#
# Update the nameserver cache information file once per month.
# This is run automatically by a cron entry.
#
# Original by Al Longyear
# Updated for BIND 8 by Nicolai Langfeldt
# Miscelanious error-conditions reported by David A. Ranch
# Ping test suggested by Martin Foster
# named up-test suggested by Erik Bryer.
#
(
echo "To: hostmaster <hostmaster>"
echo "From: system <root>"
# Is named up? Check the status of named.
case `rndc status 2>&1` in
*refused*)
echo "named is DOWN. root.hints was NOT updated"
echo
exit 0
;;
esac
PATH=/sbin:/usr/sbin:/bin:/usr/bin:
export PATH
# NOTE: /var/named must be writable only by trusted users or this script
# will cause root compromise/denial of service opportunities.
cd /var/named 2>/dev/null || {
echo "Subject: Cannot cd to /var/named, error $?"
echo
echo "The subject says it all"
exit 1
}
# Are we online? Ping a server at your ISP
case `ping -qnc 1 some.machine.net 2>&1` in
*'100% packet loss'*)
echo "Subject: root.hints NOT updated. The network is DOWN."
echo
echo "The subject says it all"
exit 1
;;
esac
dig @e.root-servers.net . ns >root.hints.new 2> errors
case `cat root.hints.new` in
*NOERROR*)
# It worked
:;;
*)
echo "Subject: The root.hints file update has FAILED."
echo
echo "The root.hints update has failed"
echo "This is the dig output reported:"
echo
cat root.hints.new errors
exit 1
;;
esac
echo "Subject: The root.hints file has been updated"
echo
echo "The root.hints file has been updated to contain the following
information:"
echo
cat root.hints.new
chown root.root root.hints.new
chmod 444 root.hints.new
rm -f root.hints.old errors
mv root.hints root.hints.old
mv root.hints.new root.hints
rndc restart
echo
echo "The nameserver has been restarted to ensure that the update is complete."
echo "The previous root.hints file is now called
/var/named/root.hints.old."
) 2>&1 | /usr/lib/sendmail -t
exit 0
Some of you might have picked up that the root.hints file is
also available by ftp from Internic. Please don't use ftp to update
root.hints, the above method is much more friendly to the net,
and Internic.
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