14.17.5. Adding a Broadcast or Multicast Server Address
To add a broadcast or multicast address for sending, that is to say, the address to broadcast or multicast NTP packets to, make use of the broadcast command in the ntp.conf file.
The broadcast command takes the following form:
broadcast address
where address is an IP broadcast or multicast address to which packets are sent.
This command configures a system to act as an
NTP broadcast server. The address used must be a broadcast or a multicast address. Broadcast address implies the
IPv4 address
255.255.255.255. By default, routers do not pass broadcast messages. The multicast address can be an
IPv4 Class D address, or an
IPv6 address. The IANA has assigned
IPv4 multicast address
224.0.1.1 and
IPv6 address
FF05::101 (site local) to
NTP. Administratively scoped
IPv4 multicast addresses can also be used, as described in
RFC 2365 Administratively Scoped IP Multicast.
