This page provides the technical information for connecting to the NTP servers run by Netnod as part of the Swedish Distributed Time Service.
This service delivers time over the Internet using NTP/NTS. We also offer PTP as a part of our premium time services. The service is operated by Netnod, monitored by RISE Research Institutes of Sweden and financed by The Swedish Post and Telecom Authority (PTS).
There are six time nodes in different locations in Sweden. The time nodes are continuously monitored and steered to follow UTC(SP). The NTP service is free to use. We also provide NTS, which you can read more about here.
NOTE: If you have mission-critical systems that need accurate and reliable time beyond the capability of software NTP implementations, you can use Netnod’s premium time services.
For redundancy, the NTP service has two independent NTP servers in each time node. Netnod provides the Internet time servers (Stratum-1) listed below. To use the NTP service, you can use the anycast address ntp.se which will direct the client to the closest available server.
If you want to get time from more than one server, you can use some or all of the unicast addresses below:
Göteborg:
gbg1.ntp.se
gbg2.ntp.se
Malmö:
mmo1.ntp.se
mmo2.ntp.se
Stockholm (Two locations):
sth1.ntp.se
sth2.ntp.se
sth3.ntp.se
sth4.ntp.se
Sundsvall:
svl1.ntp.se
svl2.ntp.se
Luleå:
lul1.ntp.se
lul2.ntp.se
The NTP servers use a custom-build FPGA-based hardware implementation for responding to the NTP requests, using IPv4 or IPv6, unsigned or signed, at a full line-rate speed of 10Gb/s per interface. They use 1PPS and 10MHz signals from the local time scales to achieve high accuracy and precision of the NTP timestamps
The NTP service uses the following IP networks and AS number:
IPv4 - 8 subnets:
194.58.200.0/24 ... 194.58.207.0/24
IPv6 - 8 subnets:
2a01:3f7:0::/48 ... 2a01:3f7:7::/48
AS:
57021
For more information about the service, please contact us here or The Swedish Post and Telecom Authority (PTS)