摘要：This article describes security mechanisms used by 3rd-7th layers in OSI/ISO network model. Many of commonly used protocols by these layers were designed with assumption that there are no intruders. Such assumption was true many years ago. The network situation has been changed for last few years and we should realize that some properties of existing protocols may be abused. Moreover, we should exchange some of them or create new versions. There are some methods and guidelines concerning secure programming, but there is also lack of guidelines about creating secure protocols. Authors see the necessity of such guideline and this article is an attempt at analysing existing solutions and selecting some universal and important patterns
关键词：AES; authentication; authorization; application; community string; dictionary ;attack; DDoS attack; DNS; DoS attack; hash function; HTTP; ICMP; IPv4; Ipv6; man ;in the middle attack; MD5; OSI/ISO model; password; port scanning; protocol; ;SHA-1; sniffing; SNMP; spoofing; SYN flooding; TCP; tunnelling; UDP
