Installing and Administering Internet Services

304 Chapter7
Configuring the Network Time Protocol (NTP)
Advanced NTP Topics
u is a value between 1 and 4. You must create a device file
/dev/wwvb% u .
• Local synchronization clock, also known as a “pseudo” clock. A system
with this type of clock configured uses the local system clock as a time
source. The address used to configure this clock is 127.127.1. u ,
where u is a value between 0 and 15 and specifies the stratum level at
which the clock runs. The local host, when synchronized to the clock,
operates at one higher stratum level than the clock. This type of clock
can be used in an isolated synchronization subnet where there is no
access to a stratum-1 time server.
See the xntpd man page for more information on configuring external
clocks.
Figure 7-3, shown earlier in this chapter, depicts an example of servers
in a synchronization subnet and their relationships to each other. Figure
7-4 shows the peer, server, and broadcast statements that are configured
for each of the servers. The system that will assume the server role is
configured on its client systems. For example, if Penelope is to be a client
of Bonita, you configure the name or address of Bonita on Penelope. You
do not need to configure Penelope as a client on Bonita.
Figure 7-4 Example Configurations
Gordo
Penelope Golden
Hugo
server bonita
peer golden
broadcast 193.100.255.255
server gordo
peer penelope
broadcast 193.100.255.255
broadcastclient yes
Bonita
server 127.127.4.1server 127.127.4.1
external
clock
external
clock