The peer statement places the local ntpd in “symmetrically active” mode as opposed to the remote server. In this mode:
the local server can be synchronized by the remote server, and
the remote server can be synchronized by the local server.
This setting is meaningful in a network of servers in which, for example, either the local or the remote server may have the better time source, depending on the load.
peer host_addr [ autokey | key][ version #][ prefer][ minpoll minpoll][ maxpoll maxpoll]
host_addr
Host address in dotted notation, which specifies the server for which the local ntpd daemon is to be set to "symmetrically active" mode. Alternatively the host’s DNS name can also be used.
autokey
NTP packets are sent and received on an authenticated basis in accordance with the autokey schema. This option and the key option are mutually exclusive.
key
NTP packets are sent and received on an authenticated basis using a schema which is based on symmetrical keys. key specifies the key identifier, the range of values extending from 1 through 65534. This option and the autokey option are mutually exclusive.
version #
Version number for outgoing NTP packets. The possible values for # are 1, 2, 3 or 4.
Default: version 4
prefer
This option can be used to mark the host specified with host_addr as "preferred" and thus select it for synchronization over other candidates that have the same values.
minpoll
Integer that specifies the minimum polling interval for NTP messages as 2minpoll seconds.
Default: 6 (64 sec)
Values permitted in BS2000: ≥ 6 (64 sec)
maxpoll
Integer that specifies the maximum polling interval for NTP messages as 2minpoll seconds.
Default: 10 (1024 sec)
Values permitted in BS2000: up to 14 (approx. 4 hours, 30 minutes)