Select at least 4 domain names from ntp.org.No one source is considered authoritative. NTP takes the time supplied from your 4 allocated time servers and uses that information collectively to calculate an accurate time.The geographically closer servers will provide the most accurate time NTP.org uses round-robin DNS to allocate the IP address of a random time server in the pool.Should be implemented with PKI infra, public key authentication, pre-shared key.Uses вЂњindustry accepted time sourcesвЂќ - For example depending on the country there may be universities that host such servers, also there are more hosted privately and at other companies.Own NTP server (Stratum 3) that obtain time from Stratum 2 servers To build your own the cost with Arduino or Raspberry module using RTC (real time clock) module is needed. Up to 1000 euro (ie TIMENET Pro, POE-powered NTP Master Time Server, incl. For example, 3600 euro + 800 for other features (Ultra high bandwidth, built in DOS detection, security hardening). You can buy your own NTP server, or even build one off hardware like Raspberry Pi.Д¬ost of own NTP server varies. Need to build or purchase as it requires special modules.Attached to time-keeping device (Stratum 0).If seeking your own, the first step is to learn more about NTP Stratum model and the NTP Pool. For others, or to maintain your own there are a few options, depending on your own resources as well as criticality. Ways to set up or configure own NTP Servers Read more about the attacks on the wiki and Black Hat EU 14 paper. Logrythm also offers a data sheet on time normalization here (fyi: not affiliated with them!). Certificates and logging infrastructure can break with minutes, hours or months of time difference. When looking at logs, time synchronization makes sure that events on different machines can be correlated accurately. When connecting to a website, knowledge of the correct time ensures that the certificate you see is current and is not compromised by an attacker. Most cryptography uses timestamps to limit certificate and signature validity periods. Inaccurate timestamps offer an inaccurate view of a sequence of events, thus making it difficult to obtain a timeframe of events in an IR. These include DNS servers, Cryptography (certificate/signature validity) like being able to connect to a https website as well as ensuring non-repudiation and integrity via maintaining accurate timestamps in logs and especially audit logs. You may have services on your network that depend on NTP and accurate timestamps in addition to using the standardized ISO8601 format.

Timenet poe