Secure Shell is a replacement for Telnet. SSH encrypts all data sent from the client to the server. This method also allows authentication with usernames, and passwords based on security certificate authentication. This method is commonly used on UNIX or Linux servers and network devices such as routers and switches.
SSL can operate at layer 4 (transport layer), in the OSI model to authenticate and encrypt traffic in the Hypertext Transfer Protocol (HTTP). By using secure VPN communication from an internet browser, between the network in the company and external users, SSL eliminates the installation of IPsec required by the VPN client software. The advantages and disadvantages of SSL are as follows.
TLS is a replacement for SLL which is a standard method for client or server encryption that starts with key exchange, authentication and standard cipher implementation. Many IP-based protocols support the use of TLS to encrypt data such as HTTP (HTTPS), SMTP, POP3, FTP and NNTP. Because almost all protocols support this encryption method, the use of this protocol is required when the server supports it.