There don’t seem to be many reasons to want to forward a local Android port (listening for connections from localhost only) to a port that can be accessed externally (via LAN, etc.). There are some applications around that allow to forward an Android local port to another one but they offer a lot of overhead, are confusing and some even require root access.
netcat for Android was the way I decided to go, it’s only known to be the “swiss-army knife” of networking. The Android source code contains a limited version of
nc which can be compiled by the simple
make nc (after having setup the build environment of course). This version of
netcat does not offer port forwarding functionality.