NTP,the,Importance,External,Ti computer NTP the Importance of External Time Reference
Gone are those times when the companies and the organisations didn't need a hi-tech system to handle them. Owing to the considerable increase in the business sector and thus, an enormous increase in the complexity of the organisational struc ----------------------------------------------------------Permission is granted for the below article to forward,reprint, distribute, use for ezine, newsletter, website,offer as free bonus or part of a product for sale as longas no changes a
NetworkTime Protocol (NTP) is one of the Internets oldest protocols and is still the standardfor time synchronisation. The success of NTP stems from its constantdevelopment (version 4 is currently in progress) and the accuracy that an NTPtime server can boast in the synchronisation of networks. Whilst anaccuracy of 1/5000th of a second can beobtained on a network under the right conditions, this accuracy is solelyreliant on whatever time reference NTP uses to synchronise with.This source could of course be unreliable, like a workstation clock as realtime chips in most computers are prone to drift and are far less accurate thanthe average digital watch. The alternative is to use a reliableUTC (Coordinated Universal Time) source. UTC is the standard for timesynchronization. It was started in 1972 after the development of atomic clocksand allows the entire globe to synchronise to the same absolute time. Thishas not only made technologies such as the Internet, GPS and communicationsatellites possible, but also has allowed industries such as airlines and thestock market to trade globally. Thesimplest way to synchronise a network to UTC has always been to use an Internettime reference. There are hundreds available such as nist.gov and most Windowssoftware has a built in utility, Windows Time (win32.exe) to synchronise thesystem clock to a reference clock over the Internet. However,Microsoft and others warn against using an Internet source as a time referenceas authentication is not possible from these sources. Authenticationis the security measure that NTP uses to ensure that a time reference istrusted. Without authentication systems are vulnerable to malicious attackssuch as hackers who could adjust a timestamp to commit fraud or a DDoS attack(Distributed Denial of Service usually caused by malicious software inundatingthe system). Not onlyare Internet times sources unauthenticated but also a survey by Nelson Minar ofMIT on over 900 Internet time references, discovered nearly half were offset byover ten seconds (one by a staggering 6 years but there were fortunately notmany peers) and less that a third where described as being useful. The reportalso discovered that many Internet time reference hosts were too far away fromtheir peers to allow accurate time synchronisation. There arehowever, several ways of ensuring a NTP server is synchronised to a reliableand stable UTC time source that is both accurate and authenticated. There aretwo systems available and both use relatively low cost equipment. The firstoption and often the easiest, is to connect to a GPS antenna and dedicated GPStime server to the network. This uses the UTC time code transmitted by the GPSsatellites, as long as the antenna has a good view of the sky. Alternativelyspecialist broadcast signals transmit a timestamp in several countries. InBritain it is referred to as MSF and broadcast from Cumbria by the NationalPhysics Laboratory at 60 kHz but can be picked up as far away as 1000 km,although similar systems operate in Germany, France and the US. These radioreferenced NTP servers are vulnerable to interference but traditionally were ofa lower cost than GPS receivers however, advances in technology mean thedifference is now minimal. Theintegrity of a time source used by a NTP time server is therefore highlyimportant and whist system administrators are all too willing to invest inexpensive firewalls and anti-viral software to protect their networks manyneglect their time servers security which after all, may not be telling themthe right time anyway!
NTP,the,Importance,External,Ti