SMTP Tunnel Proxy
A high-speed covert tunnel that disguises TCP traffic as SMTP email
...The tool supports modern TLS encryption (STARTTLS) with HMAC-SHA256 authentication, per-user secrets, IP whitelisting, and multiplexed connections over a single tunnel. With a simple installer and systemd service setup, users can quickly deploy it on a Linux VPS as a tunneled access point, then connect from Windows, macOS, or Linux clients using auto-generated client packages. The project is useful for environments where standard VPNs or proxies are blocked, offering a combination of performance and stealth.