In the 21st century, the problem of cyber crime was developing. The problem itself is widely spread and includes not only big companies but also individuals. In order for one to defend themselves from these sorts of threats it takes not only knowledge and common sense but also one's own ability to anticipate danger. It is very important to acquire the knowledge of these dangers ahead of time, for information to be verified and for advice to be applicable. For this reason, a survey was conducted among students in order to see how much they know about safety on the internet and also to gauge how risky their behaviour is when it comes to certain situations. Since most students are 21st century children, they constitute a perfect survey sample. Before delving into the survey results, some important notions and ideas had to be defined and commented on. Safe online behaviour was described as well as behaviour that poses a threat to the user. Different ways to put a stop to these threats, like antivirus software and firewalls, were also described. At the end, problems like e-mail spam and public online security when it comes to connecting to public Wi-Fi networks were also mentioned.