port forwarding alternatives?

Question

My question is about alternatives to portforwarding if i want a service to be listening on a tcp port?

i am connected to the internet through my phone wireless hotspot and i am using kali linux is there any alternatives to portforwarding ? also my ISP block portforwarding on routers except if you have a static IP which is highly expensive , i heard that this can be achieved through vpn if so are there any free vpn that allow to use this feature ?

Solution

There are no Home/SOHO alternatives to Port Forwarding, per se, but it is not always necessary to manually administer port forwarding rules. There is also a means to bypass the need for port forwarding via the Reverse Tunneling technique, using VPN or SSH tunnels.

UPNP is a protocol that, among other things, allows a services to ask the router to open a port for it. UPNP is most useful in home scenarios, but carries some risks from a security perspective, in that malware operating on your network can issue commands to your NAT configuration that compromise your security.

Another option is a DMZ, where the router sends unsolicited incoming traffic to a default IP (at least in home scenarios; enterprise hardware has more sophisticated options), so no port forwarding is required to access services on that port, but in exchange, the entire surface area of the server is exposed to the public Internet, so they must be stripped down to enable only allowed services, and to secure their configuration as much as is feasible. In firewall circles, this kind of configuration is often called a Bastion Host.

Ultimately, your ISP may trump any thing you may try, if they own the router, or block unsolicited incoming traffic upstream from your router. Using a VPN to create a reverse tunnel is an option, though it does require some technical sophistication. A better approach would be to rent a VPS instead that you VPN into, so you control the remote endpoint, and feed traffic incoming on the VPS into the VPN tunnel, and onto your LAN via reverse tunneling.