Ncat Has an HTTP Proxy Listener Mode
Use Ncat’s documented listen-mode proxy support rather than expecting a plain TCP relay to parse proxy requests.
Ncat, the Nmap implementation, can act as an HTTP proxy in listen mode. A local listener can be specified as:
ncat -l 127.0.0.1 8080 --proxy-type httpConfigure the client with an HTTP proxy at 127.0.0.1:8080. Ncat documents GET, HEAD and POST forwarding plus CONNECT for TCP tunnels in this mode.
Only HTTP is supported as the server-side proxy type. Ncat’s SOCKS client support does not imply a SOCKS server mode.
The executable matters: a different program named nc or netcat may provide only ordinary TCP listening and copying. Such a relay does not gain request parsing by using a proxy-looking port.
Ncat describes this proxy as a temporary connection helper. The loopback binding keeps the example local rather than publishing an everyday internet proxy.