HP-UX Internet Services Administrator's Guide (August 2003)

Configuring NTP
Getting Started with NTP
Chapter 4 59
Available Time Sources
The most common time distribution mechanisms from which you can
draw time are:
• Public time server (phone or modem) via the Internet
• Local clock impersonators
• Radio receiver – Terrestrial and satellite broadcast
Public Time Server
You can connect to public time servers via the Internet free of charge for
a limited time. Public time servers also provide dial-up access through a
modem. This is the cheapest and most popular method. One of the main
disadvantage of this option is that all the networks cannot use the public
time server because they are protected behind firewalls.
Many other time servers are available that you can access. HP provides a
public time server, which is located in Cupertino, California. You can use
this time server if you are located in North America. The following lists
the details for this time server:
ntp-cup.external.hp.com (192.6.38.127)
Location: Cupertino, CA (SF Bay Area) 37:20N/122:00W
Synchronization: NTP3 primary (GPS), HP-UX Service Area: West
Coast USA
Access Policy: open access
Contact: [e-mail]
Note: no need to notify for access, go right ahead!
NOTE An enterprise can implement its own hierarchy of NTP time servers,
including the stratum-1 servers. If your administrative domain is part of
an enterprise-wide Internet, you must verify for available NTP resources
in your enterprise. If your administrative domain does not have access to
lower-stratum time servers, NTP servers on the Internet are available
that provide public time synchronization. You can use stratum-1 and
stratum-2 servers only with the permission of the administrator; you
must always check with the administrator before usingan NTP server on
the Internet.