ptunnel is Rust program that tunnels connections through HTTPS enabled proxy (supporting CONNECT method), thus ptunnel can be used to sneak any protocol through proxy - for instance IMAP, SMTP, SSH etc (unless proxy is doing additional checks on forwarded protocol - for instance that it is TLS). ptunnel is using asynchronous I/O (via tokio module) so it is very effective and can scale well.
Typical usage is for instance if you want to access gmail via corporate proxy -
locally on your machine you run ptunnel as ptunnel -p your_proxy_host:port 9993:imap.gmail.com:993 5587:smtp.gmail.com:587 and set your email client to use localhost:9993 as your IMAP server and localhost:5587 as your SMTP server - this approach has one downfall - SSL/TLS - because now SSL certificates will not match the hostname - so you'll need to add security exception to your email client.
On linux we can do bit better - use /etc/hosts to map hostnames imap.gmail.com and smtp.gmail.com to local interface:
127.0.0.1 imap.gmail.com
127.0.0.1 smtp.gmail.com
and use different parameters for ptunnel: ptunnel -p your_proxy_host:port 9993:gmail-imap.l.google.com:993 5587:gmail-smtp-msa.l.google.com:587 and setup email client to imap.gmail.com:9993 and smtp.gmail.com:5587 - this will make SSL to work without problems.
Mobile users may connect to different networks, where some (corporate network) have proxy and others (home, public wifis) do not. ptunnel is able to cope with such situations, because if it cannot connect to proxy, it falls back to direct connetion to remote host. Thus you can easily move between networks and ptunnel will handle it.
You can supply proxy host:port argument to ptunnel program as -p host:port or you can use standard environment variable https_proxy, which is in form of URL http://host:port.
Program also supports basic authentication with proxy (via --user and --password program arguments).
Clone repository and build with cargo build --release (to install cargo and rust follow instructions here https://www.rustup.rs/)
After successful compilation copy binary target/release/ptunnel somewhere on your PATH.
This program is licensed under MIT license