What is port forwarding?

Port Forwarding is a technology that allows normally unsecure communications (like email or web surfing) to be encrypted, thereby ensuring your privacy and the safety and integrity of your data.

When would I need it?

Anytime you use a computer connected to a network, it is possible for others on that same network to examine, steal, intercept, and snoop on your communications with other computers.

This can happen when you send or receive an email, copy a file from one computer to another, join a conversation in a chat room, or use popular instant messaging programs. These are just a few examples - there are hundreds of ways to accidentally expose your personal or corporate information to others on the network.

How is port forwarding implemented?

Port Forwarding is a software feature of Secure Shell (SSH), which was originally created to allow system administrators and computer operators to securely login to a computer from a remote location. In the beginning, utilities like telnet and rlogin were used to do this, but the username and password was sent "in-the-clear", which allowed others to intercept and hack these systems. SSH was designed to create a secure, encrypted connection between the two computers so others could not decode the data being sent.

During the development of SSH, software engineers added a feature known as Port Forwarding to the specification. This feature allowed unsecure communications destined for the remote computer to be intercepted, encrypted, and then re-routed through the SSH secure connection. On the remote computer, the communications would be received, decrypted, and delivered to the appropriate application.

Computers communicate with other computers by using a combination of IP address and a program-assigned port number. The IP address specifies the computer system, and the port number identifies a unique network connection that's assigned to an application, such as an email server. For example, when your desktop computer retrieves email from a remote server, it connects to port 110, which is used to communicate with the POP3 email application. This connection is not encrypted, so any email you retrieve can be seen by anyone monitoring the network.

When your computer is setup to use SSH Port Forwarding, your email client (Outlook, Eudora, etc.) is redirected to port 22, which is the encrypted SSH connection. On the remote host where your email resides, the encrypted data is received over port 22, decrypted, and then re-routed to port 110. You can now read your email over a secure connection, secure in the knowledge that no one else can view your private or corporate communications.

Which Century products support port forwarding?

Port forwarding is supported in TinyTERM Plus, TinyTERM Thin Client and TinyTERM Web Server version 4.3

How do I setup port forwarding in TinyTERM Version 4.3?

• Open a new session in TinyTERM.
• Click on Edit | Session Properties.
• Change the connection type to SSH and click the Apply button.
• Click on the Port Forwarding tab.
• Enter a name for the connection.
• Choose whether to forward a local TCP/IP port to a remote host (local to remote forwarding), or forward a remote port to the local PC (remote to local forwarding).
• Enter the local port that will forward or receive forwarding.
• If the SSH server is not the remote system, check the "Remote host is different machine from SSH server machine" box and enter a remote host name or IP address.
• Enter the TCP/IP port for the remote host.
• Enter the name of the local PC application to run, or click the Browse button to select one.
• Enter any command-line parameters for the local PC application.
• Click the Add button to add the connection to the list. The next time you open this TinyTERM session, the port forwarding you set up will be active.