Whenever you create SSH tunnel or port forwarding, by default, it is only available for the local host. Unless specified, it listens to the loopback IP address or the localhost. This IP address is not accessible from outside hosts, which causes the forwarded port to not be available from outside.

You can allow public access to your SSH tunnel by creating a port forwarding or tunnel that listens on an accessible IP address and configure necessary firewall rules to allow incoming connection to the tunnel.

Steps to configure public access to SSH tunnel:

  1. Get IP addresses of your host.

    $ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet scope host lo        valid_lft forever preferred_lft forever     inet6 ::1/128 scope host         valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000     link/ether 00:0c:29:08:63:73 brd ff:ff:ff:ff:ff:ff     altname enp2s1     inet brd scope global dynamic noprefixroute ens33        valid_lft 66553sec preferred_lft 66553sec     inet6 fe80::fc5d:1d5c:ae0e:68f1/64 scope link noprefixroute         valid_lft forever preferred_lft forever

  2. Create a tunnel or port forwarding by specifying IP address to listen to.

    $ ssh -fN -D [email protected]'s password:
  3. Check if tunnel currently running on specified IP address.

    $ ss -natp | grep 8080 LISTEN 0      128*    users:(("ssh",pid=2966,fd=4))

  4. Configure firewall to allow remote access to the tunnel port.

    $ sudo ufw allow 8080 #Ubuntu and Debian variance $ sudo firewall-cmd --zone=public --permanent --add-port=8080/tcp && sudo firewall-cmd --reload #CentOS and Red Hat variance

  5. Access tunnel from other host to test.

    $ curl --proxy socks5:// https://ifconfig.me