This note outlines two changes to NTP services at York.

Back in April, a fairly serious exploit was discovered in several
versions of unix based NTP software. At that time, we were forced to
migrate our NTP servers to ensure other services weren't
compromised by this vulnerability.

After much testing, CNS has moved NTP services back to their
original servers.  We also added two new Stratum 3 NTP servers.
One at Glendon and one for computers located behind the
administrative firewall.

While the servers have changed, the hostnames for our main NTP
servers remain the same:

ntp1.time.yorku.ca
ntp2.time.yorku.ca
ntp3.time.yorku.ca

The hostnames for the new NTP servers are:

ntp-glendon.time.yorku.ca
ntpfw1.time.yorku.ca

Depending on your operating system, it may be necessary to restart
your NTP software to force your NTP client to resolve the hostnames
to match the new server IP addresses.  In order to give people time
to adjust their settings, CNS will leave the NTP servers running on
the old IP addresses until February 1, 2002.

On February 1, 2002, CNS will standardize our naming convention for
the central NTP servers at York.  On this date, the server
hostnames, will be reduced to the 5 basic addresses listed above.
All other DNS cnames and aliases will be deleted.

Information on NTP services can be found at:

http://www.yorku.ca/netops/ntp.html

Questions or concerns about these outages, should be directed to
the CNS Helpdesk in the Steacie Science Library Building, (voice:
416-736-5800, email: [log in to unmask]).