The Network Time Protocol (NTP) is a protocol for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks. NTP uses UDP port 123 as its transport layer. It is designed particularly to resist the effects of variable latency.
NTP sometimes greatly slows down your Ubuntu’s boot time. To disable it just do a simple code...

A look at various ways to secure the root account against system users and some in-use methods that seem to cause more harm than good.