SSH, the Shell Secure abbreviation developed by the IETF network working group (Working Group Network). SSH is aimed at the establishment of the application layer and the transport layer based on the security agreement. Traditional network service programs, such as FTP, pop and telnet is not actual safe; because they are on the network with plain text transmission of data.User account and password is accessed easily by man in the middle attack mode of attack. That is to say the existence of another person or a machine posing as a real server to receive the user data transmitted to the server, and then posing as the user data to the real server. However SSH is currently more reliable, designed for remote login sessions and other network services to provide security protocols. Using SSH protocol can effectively prevent information leakage in the process of remote management. You can encrypt all the data transmitted, but also to prevent the DNS and IP through SSH Another advantage of SSH for its transmission of the data is compressed, so you can speed up the transmission. SSH has a lot of functions, it can replace the Telnet, but also for FTP, POP, or even for the PPP to provide a secure channel. your comments?