Information systems consist of information and data that make a complex system aimed to accomplish the objectives that can be achieved if we manage the system properly. The Internet is a global network that by using Internet Protocol, enables communication and access to various services. According to transport protocol TCP (Transmission ControlProtocol), Internet architecture is called TCP / IP architecture that can be described using the TCP / IP model and it consists of four layers: physical, network, transport, and application layer. Some of the sources of threat to the TCP / IP network are malicious programs which include viruses, worms, Trojan horses, spyware, adware, hoaxes and many others that can be downloaded by downloading files from the Internet and illegal copies various software. They can also be present in electronic messages or we can download them when we open pop-up advertisements. DoS and DDoS attacks deny service to customers by filling the computer with more data than a computer system can handle. To protect from malware programmes and attacks, it is required to establish anti-virus software to identify and eliminate sources of danger or encryption of data where data is encoded in unreadable form. IPSec protocol is used for protection of data in the TCP / IP network so that secure communication and exchange of data between two or more computers on the Internet can be enabled. Firewalls block certain packages in traffic and blocks other data if identifies some threat to our computer, and a proxy server can be set up between a firewall for faster and more secure data exchange. Honeypot and honeynet are computer systems for enticing and trapping attackers.