Network Time Protocol (NTP) is an Internet protocol used for the transfer of accurate time, That time providing accurate information when it can be obtained and maintained in a networkMost UNIX and Linux operating systems provide time synchronization built the NTP (Network Time Protocol) daemon. If the NTP service is not available UNIXLinux version, NTP version 4 is open source and can be easily downloaded and configured, compiled and installed on www. NTP. Org. Network Time Protocol is the distribution of service time standard across TCP / IP. It provides an accuracy of 10-50 milliseconds, depending on the characteristics of the synchronization source and network paths. The configuration file fro the NTP daemon called NTP. conf and contains a list of reference clocks to be synchronized. server command ‘specifies the reference clock, all characters after the’ # ‘are comments such as time-to server. NIST. Governor # public NTP servers: NISTdriftfile / var / lib / ntp / NTP. driftThe script identifies the drift, which has the drift (sometimes known as the frequency of an error). This value may be offset by NTP to ensure greater accuracy. When configured, NTP can be controlled by stop”commands”’ntpq ntpd start ntpd-p ‘(status display) may also authenticate NTP timing resources Note: We recommend that you set a time server with a source rather than authentication hardware that where there is Internet. authentication codes specified in the NTP. rows of keys. Specialist NTP servers are available that can receive transmissions from either GPS or broadcasts national reference time. They are relatively cheap and the signal is authentic by providing a secure time reference. The authentication password can be specified by the NTP server and its clients. NTP keys or passwords are stored in the NTP. key file in the following format: number M (M is for MD5 encryption), password: 1 MM M my3rdpasswordAuthentication mypassword3 my2ndpassword5 NTP has been developed to prevent malicious synchronization with the system have been developed as a firewall to protect networks from attacks , but like any security system only works if used.