软件包：rsendmail（1.1.4）
email delivery over SSH and restricted sendmail
This command aims at replacing the builtin `sendmail` command which gives too much privileges to the caller. For example, Postfix's sendmail(1) command can list the mail queue (`-bp`), rehash the alias database (`-bi`), start a daemon (`-bl`, `-bd`), or flush the queue (`-q`); all remnants of the old Sendmail binary, which probably is Turing-complete on its own.
Instead, rsendmail can easily queue mails on a system without giving any extra privileges to the client. In turn, this makes configuring a satellite system like a laptop or a workstation as simple as adding an SSH key to an `authorized_keys` file. That key can then send email, but *only* send email: no shell access or server management.
This can of course be accomplished by a regular SMTP client, but that requires passwords, and passwords are weak.