How to use the port forwarding of SSH to encrypt unsafe services

Author: Wu Ating (http://www.linuxforum.net)
One. Brief introduction:
Most people know that SSH is used to replace the R command set, which is used for encrypted remote logins, file transfers, and even encrypted
FTP (SSH2 built-in), so SSH becomes one of the most widely used services, and SSH has another very
With the function of its port forwarding tunnel function, using this function, so that some unsafe services like POP3,
Smtp,ftp,ldap and so on through the encrypted tunnels of SSH, and then, since the services themselves are unsafe,
Passwords and content are transmitted in clear text, and there are no other intermediate media listening.
Two. Icon:
The encrypted tunnel of SSH protects only the security of intermediate transmissions, making it impossible for any usual sniffer software to obtain
Send content. The following figure:
Assume that both the client and the server are running Linux and take POP3 as an example.
C (POP3 server:s) S
_______               ________
|               |        | |
|        |________pop3___________ >| |
|_____| |______|
(Figure I: normal POP3)
(Figure I: normal POP3)
C (POP3 server:c) S (POP3 client:s)
_______               ________
|               |        | |