pbnc

Simple userspace TCP port bouncer

pbnc runs in userland and acts as a simple TCP port forwarder. It has a single-threaded design (uses select(), does not fork). It can handle multiple targets with an unlimited number of clients (at least in theory), and supports simple IP-based access control. Since pbnc works on network level, it does not care about the application protocol. It can tunnel FTP (control connection), SSH, HTTP and all other protocols using TCP communication. Application-level SSL/TLS encryption is also no problem. See also: https://duncanthrax.net/pbnc/