SSH local port forwarding: how a local preview connection works

SSH local port forwarding: Understanding native preview channels. The local entrance reaches the server's internal services through the SSH tunnel; the browser accesses the local port; the SSH encrypted channel; the service maintains internal access — Original article illustration. Some labels may be in Chinese; see the text and linked sources for details.

Where does the connection go?

Local port forwarding allows the client to listen on a local address and then access a target reachable by the server through an SSH session. The server's 127.0.0.1 and your computer's 127.0.0.1 point to different devices.

Limit listening range

When previewing on this machine, bind the local listening address to 127.0.0.1 to limit the entrance to the current computer. Don’t expand the monitoring range at will when you don’t understand the impact.

Session life cycle

Forwarding relies on the SSH session, closing the session will close the channel. In the mode of only forwarding and not running remote commands, it may be normal that there is no new output on the terminal, but it should still be verified with the actual page request.

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