An SSH tunnel (or SSH Port Forwarding) is like creating a secure, encrypted pipe between your computer and a remote server.
It allows network traffic to “travel” inside the SSH connection, allowing you to access services that are protected by a firewall or are only accessible locally within that server.
It is the most common way to access tools like Nexus, databases, or control panels that you don’t want to expose directly to the entire internet.
ssh -L 8031:localhost:8081 axeldamian@server.axxelin.com -p 53000- -L : Local SSH tunnel (Local Forwarding): Tells SSH that you want to map a port from your local machine to the server
- The first port is for your computer “here” and the second is for the service “there”
- 8031 (First port): This is the port on your computer. When you open your browser and type localhost:8031, you will be entering the tunnel.
- The tunnel would travel to the server.
- The server would deliver that traffic to its own port 8081 (where Nexus is located).
- localhost:8081 (Destination): This is where the traffic goes once it reaches the server. In this case, it tells the server: “what you receive through the tunnel, send it to your own port 8081.”
- axeldamian@server.axxelin.com: Your username and your server address.
- -p 53000: Indicates that the server’s SSH service is not on the standard port (22), but on 53000.
and access it from the web browser on the local computer
http://localhost:8031/
You’re “cheating” the system
Executing this command opens a bridge.
You open Chrome on your local PC, type http://localhost:8081 and magically you see the Nexus interface on the server, because the traffic travels encrypted through SSH port 53000.
see the urls:
server.axxelin.com is a DNS domain name that is mapped to a public IP address; to avoid typing the IP address, I use the DNS domain
Port 8081 on the server/PC is open (with port forwarding) and on the local PC port 8031 (is not open)
public_ip_server:open_port_with_port_forwarding redirected to private_ip:8081
Your Browser (:8081) -> SSH Tunnel (Port 53000) Server -> Nexus (:8081)