RouterOS v6 implements the SNTP protocol defined in RFC4330, manycast mode is not supported. SNTP client is included in the system package. To use an NTP server, ntp package must be installed and enabled.

RouterOS v7 main package includes NTP client and server functionality, which is based on RFC5905.

The client configuration is located in the /system ntp client console path, and the "System > SNTP Client" (RouterOS version 6), "System > NTP Client" (RouterOS version 7) WinBox window. This configuration is shared by the SNTP client implementation in the system package and the NTP client implementation in the ntp package. When ntp package is installed and enabled, the SNTP client is disabled automatically.

RouterOS version 6

SNTP Client properties:

Property	Description
enabled (yes, no default: no)	Enable SNTP client for time synchronization
mode (broadcast, unicast, filed is read-only)	Mode that the SNTP client will operate in. If no NTP servers are configured broadcast mode will be used. If there is a dynamic or static NTP server IP address or FQDN used it will automatically switch to unicast mode.
primary-ntp (IP address default: 0.0.0.0)	IP address of the NTP server that has to be used for time synchronization. If both values are non-zero, then the SNTP client will alternate between the two server addresses, switching to the other when the request to the current server times out or when the "KoD" packet is received, indicating that the server is not willing to respond to requests from this client. The following formats are accepted: - ipv4 - ipv6
secondary-ntp (IP address default: 0.0.0.0)	see primary-ntp
server-dns-names (Comma separated domain name list default: )	To set the NTP server using its domain name. The domain name will be resolved each time an NTP request is sent. Router has to have /ip dns configured.

Status

active-server (IP address; read-only property) : Currently selected NTP server address. This value is equal to primary-ntp or secondary-ntp.
poll-interval (Time interval; read-only property) : Current interval between requests sent to the active server. The initial value is 16 seconds, and it is increased by doubling to 15 minutes.

Last received packet information

Values of the following properties are reset when the SNTP client is stopped or restarted, either because of a configuration change, or because of a network error.

last-update-from (IP address; read-only property) : Source IP address of the last received NTP server packed that was successfully processed.
last-update-before (Time interval; read-only property) : Time since the last successfully received server message.
last-adjustment (Time interval; read-only property) : Amount of clock adjustment that was calculated from the last successfully received NTP server message.
last-bad-packet-from (IP address; read-only property) : Source IP address of last received SNTP packed that was not successfully processed. Reason of the failure and time since this packet was received is available in the next two properties.
last-bad-packet-before (Time interval; read-only property) : Time since the last receive failure.
last-bad-packet-reason (Text; read-only property) : Text that describes the reason of the last receive failure. Possible values are:
- bad-packet-length - Packet length is not in the acceptable range.
- server-not-synchronized - Leap Indicator field is set to "alarm condition" value, which means that clock on the server has not been synchronized yet.
- zero-transmit-timestamp - Transmit Timestamp field value is 0.
- bad-mode - Value of the Mode field is neither 'server' nor 'broadcast'.
- kod-ABCD - Received "KoD" (Kiss-o'-Death) response. ABCD is the short "kiss code" text from the Reference Identifier field.
- broadcast - Received proadcast message, but mode=unicast.
- non-broadcast - Received packed was server reply, but mode=broadcast.
- server-ip-mismatch - Received response from address that is not active-server.
- originate-timestamp-mismatch - Originate Timestamp field in the server response message is not the same as the one included in the last request.
- roundtrip-too-long - request/response roundtrip exceeded 1 second.

Client settings example:

To check the status of the NTP client in CLI, use the "print" command

[admin@ntp-example_v6] > /system ntp client print 
           enabled: no
       primary-ntp: 0.0.0.0
     secondary-ntp: 0.0.0.0
  server-dns-names: 
              mode: unicast

To enable the NTP client and set IP addresses or FQDN of the NTP servers:

[admin@ntp-example_v6] > /system ntp client set enabled=yes
[admin@ntp-example_v6] > /system ntp client print 
             enabled: yes
         primary-ntp: 0.0.0.0
       secondary-ntp: 0.0.0.0
    server-dns-names: 
                mode: unicast
     dynamic-servers: x.x.x.x, x.x.x.x
       poll-interval: 15s
       active-server: x.x.x.x
    last-update-from: x.x.x.x
  last-update-before: 6s570ms
     last-adjustment: -1ms786us
[admin@ntp-example_v6] > /system ntp client set primary-ntp=162.159.200.123
[admin@ntp-example_v6] > /system ntp client print 
           enabled: yes
       primary-ntp: 162.159.200.123
     secondary-ntp: 0.0.0.0
  server-dns-names: 
              mode: unicast
   dynamic-servers: x.x.x.x, x.x.x.x
     poll-interval: 16s
     active-server: x.x.x.x

NTP Server settings:

Server configuration is located in /system ntp server

Property	Description
enabled (yes or no; default value: no)	Enable NTP server
broadcast (yes or no; default value: no)	Enable certain NTP server mode, for this mode to work you have to set up broadcast-addresses field
multicast (yes or no; default value: no)	Enable certain NTP server mode
manycast (yes or no; default value: no)	Enable certain NTP server mode
broadcast-addresses (IP address; default value: )	Set broadcast address to use for NTP server broadcast mode

Example:

Set up an NTP server for the local network that is 192.168.88.0/24

/system ntp server set broadcast=yes broadcast-addresses=192.168.88.255 enabled=yes manycast=no

RouterOS version 7

NTP Client properties:

Property Description

enabled (yes, no default: no) Enable NTP client for time synchronization

mode (broadcast, manycast, multicast, unicast) Mode that the NTP client will operate in

NTP servers

The list of NTP servers. It is possible to add static entries.

The following formats are accepted:

- FQDN ("Resolved Address" will appear in the "Servers"- window in an appropriate column if the address is resolved) or IP address can be used. If DHCP-Client property use-peer-ntp=yes - the dynamic entries advertised by DHCP
- ipv4
- ipv4@vrf
- ipv6
- ipv6@vrf
- ipv6-linklocal%interface

vrf (default: main) Virtual Routing and Forwarding

Servers (Button/Section)

A detailed table of dynamically and statically added NTP servers (Address, Resolved address, Min Poll, Max Poll, iBurst, Auth. Key)

To set the NTP server using its FQDN. The domain name will be resolved each time an NTP request is sent. Router has to have /ip/dns configured.

Peers

Current parameter values

[admin@ntp-example_v7] > /system/ntp/monitor-peers
 type="ucast-client" address=x.x.x.x refid="y.y.y.y" stratum=3 hpoll=10 ppoll=10 root-delay=28.869 ms root-disp=50.994 ms 
   offset=-0.973 ms delay=0.522 ms disp=15.032 ms jitter=0.521 ms 
-- [Q quit|D dump|C-z pause]

Keys

NTP symmetric keys, used for authentication between the NTP client and server. Key Identifier (Key ID) - an integer identifying the cryptographic key used to generate the message-authentication code.

Status

synchronized, stopped, waiting, using-local-clock - Current status of the NTP client
Frequency drift - The fractional frequency drift per unit time.
synced-server - The IP address of the NTP Server.
synced-stratum - The accuracy of each server is defined by a number called the stratum, with the topmost level (primary servers) assigned as one and each level downwards (secondary servers) in the hierarchy assigned as one greater than the preceding level.
system-offset - This is a signed, fixed-point number indicating the offset of the NTP server's clock relative to the local clock, in seconds.

NTP Server settings:

Server configuration is located in /system ntp server

Property	Description
enabled (yes or no; default value: no)	Enable NTP server
broadcast (yes or no; default value: no)	Enable certain NTP server mode, for this mode to work you have to set up broadcast-addresses field
multicast (yes or no; default value: no)	Enable certain NTP server mode
manycast (yes or no; default value: no)	Enable certain NTP server mode
broadcast-addresses (IP address; default value: )	Set broadcast address to use for NTP server broadcast mode
vrf (default: main)	Virtual Routing and Forwarding
use-local-clock (yes or no; default value: no)	The server will supply its local system time as valid if others are not available.
local-clock-stratum	Manually set stratum if use-local-clock=yes
auth-key (default value: none)	NTP symmetric key, used for authentication between the NTP client and server. Key Identifier (Key ID) - an integer identifying the cryptographic key used to generate the message-authentication code.

Log messages

SNTP client can produce the following log messages. See the article "log" on how to set up logging and how to inspect logs.

ntp,debug gradually adjust by OFFS
ntp,debug instantly adjust by OFFS
ntp,debug Wait for N seconds before sending the next message
ntp,debug Wait for N seconds before restarting
ntp,debug,packet packet receive an error, restarting
ntp,debug,packet received PKT
ntp,debug,packet ignoring received PKT
ntp,debug,packet error sending to IP, restarting
ntp,debug,packet sending to IP PKT

Explanation of log message fields

OFFS - difference of two NTP timestamp values, in hexadecimal.
PKT - dump of NTP packet. If the packet is shorter than the minimum 48 bytes, it is dumped as a hexadecimal string. Otherwise, the packet is dumped as a list of field names and values, one per log line. Names of fields follow RFC4330.
IP - remote IP address.

NOTE: the above logging rules work only with the built-in SNTP client, the separate NTP package doesn't have any logging facilities.