... requireshuman management to find and analyze attacks, make rules, and deploy the rules. The most serious disadvantage ofthese signature schemes is that it is difficult to detect theunknown and new ... new Hidden Markov Model-based approach and the updated performance analysis, and overall parts likeabstract, introduction, and conclusion are rewritten, and the main approach in Section 4 was also ... Scanning: insidesniffer, Ipsweep, Mscan, Nmap, que-so, r esetscan, satan, saint;(iii) Covert Channel: ICMP covert channel, Http covertchannel, IP ID covert channel, TCP SEQ and ACKcovert channel,...