Comproportionation or symproportionation is a chemical reaction where two reactants, each containing the same element but with a different oxidation number, will form a product in which the elements involved reach the same oxidation number. Potassium permanganate contains manganese with oxidation number of +7 and reacts with a manganese compound having oxidation number +2 to yield manganese(IV) oxide (manganese dioxide) with oxidation number +4, potassium hydroxide and water.
Secure Shell, or SSH, is a cryptographic (encrypted) network protocol to allow remote login and other network services to operate securely over an unsecured network. SSH provides a secure channel over an unsecured network in a client-server architecture, connecting an SSH client application with an SSH server.
SSH Tunnel. This page explains what SSH tunneling (also called SSH port forwarding) is, how it can be used to get into an internal corporate network from the Internet, and how to prevent SSH tunnels at a firewall. SSH tunneling is a powerful tool, but it can also be abused.