Extensive theoretical and practical information in the field of methods and methods for ensuring the security of computer networks has been systematized. Measures to ensure the security of computer systems as an organic part of the general information system of the enterprise are considered; methods of protecting computer software and the information they process; network aspects of information transfer between nodes of a computer network (security issues of network protocols and services); basic technologies used to protect information in a computer network, such as encryption, authentication, authorization. organization of a secure channel and others, which to one degree or another are the basis of all methods for ensuring the security of computer networks.