Synchronize and Coordinate Time Distribution Using NTP

Configure NTP

To configure NTP on the switch, include the ntp statement at the [edit system] hierarchy level:

[edit system]
ntp {
    authentication-key number type type value password;
    boot-server (address | hostname);
    broadcast <address> <key key-number> <version value> <ttl value>;
    broadcast-client;
    multicast-client <address>;
    peer address <key key-number> <version value> <prefer>;
    server address <key key-number> <version value> <prefer>;
    ntp source-address routing-instance routing-instance-name;
    trusted-key [ key-numbers ];
}

Configure NTP Boot Server

When you boot the switch, it issues an ntpdate request, which polls a network server to determine the local date and time. You need to configure a server that the switch uses to determine the time when the switch boots. Otherwise, NTP will not be able to synchronize to a time server if the server’s time appears to be very far off of the local switch’s time.

• To configure the NTP boot server, include the set ntp server statement at the [edit system ntp] hierarchy level. Specify either the IP address or the hostname of the network server:

  content_copy zoom_out_map

  [edit system ntp]
  set server (address | hostname); 
  

• Prior to Junos OS Release 15.1, to configure the NTP boot server, include the boot-server statement at the [edit system ntp] hierarchy level:

  content_copy zoom_out_map

  [edit system ntp]
  boot-server (address | hostname); 
  

Specify a Source Address for NTP Server

For IP version 4 (IPv4), you can specify that if the NTP server configured at the [edit system ntp] hierarchy level is contacted on one of the loopback interface addresses, the reply always uses a specific source address. This is useful for controlling which source address NTP will use to access your network when it is either responding to an NTP client request from your network or when it itself is sending NTP requests to your network.

To configure the specific source address that the reply will always use, and the source address that requests initiated by NTP server will use, include the source-address statement at the [edit system ntp] hierarchy level. The source-address is a valid IP address configured on one of the router or switch interfaces.

[edit system ntp]
user@host#set source-address source-address

For example:

[edit system ntp]
user@host# set source-address 10.1.4.3

Starting in Junos OS Release 13.3, and Junos OS Evolved Release 20.2R1 you can configure the source address using the routing-instance statement at the [edit system ntp source-address source-address] hierarchy level:

As a result, while sending NTP message through any interface in the ntp-source-test routing instance, the source address 12.12.12.12 is used.

Specify one source address per family for each routing instance,

[edit system ntp] 
user@host# set source-address source-address routing-instance routing-instance-name

For example:

[edit system ntp] 
user@host# set source-address 10.1.4.3 routing-instance ntp-instance

When configuring the NTP service in the management VRF (mgmt_junos), you must configure at least one IP address on a physical or logical interface within the default routing instance and ensure that this interface is up in order for the NTP service to work with the mgmt_junos VRF.

[edit firewall filter Loopback-Interface-Firewall-Filter]
term Allow-NTP {
    from {
        source-address {
            172.17.27.46/32; // IP address of the NTP server
            10.1.4.3/32 routing-instance ntp-instance; // Source address specified for the NTP server            }
        then accept;
    }
}