SMTP proxy over SSH connections

ssh-smtp creates an SMTP service that recognizes MAIL FROM SMTP commands and connects to the appropriate server using SSH, and interconnects the socket with the remote SMTP server. This way, the confidentiality, integrity and authentication of the SMTP connection is handled by SSH, thus

• existing SSH keys can be used,
• there's no need for TLS configuration, SSH provides PFS by using DH, and
• if you already have an SSH connection open, multiplexing avoids the need to open another TCP socket, if your SSH configuration supports it.

Compiling

Execute qmake && make which should compile everything and produce ssh-smtp

Usage

Linux users should modify ssh-smtp.sample.conf according to the comments, and save it into ~/.config/dnet/ssh-smtp.conf. Windows and Mac OS should work as well, but I'll leave that as an exercise to the reader (see Registry/plist).

License

The whole project is licensed under MIT license.

Runtime dependencies

• QT4 Core (Debian/Ubuntu package: libqtcore4)
• QT4 Network (Debian/Ubuntu package: libqt4-network)

Build dependencies

• QT4 development files (Debian/Ubuntu package: libqt4-dev)