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Spiped – secure pipe for SSH, SMTP, etc.
The spiped secure pipe daemon
To set up an encrypted and authenticated pipe for sending email between two systems (in the author's case, from many systems around the internet to his central SMTP server, which then relays email to the rest of the world), one might run on a server and after copying keyfile to the local system, run at which point mail delivered via localhost:25 on the local system will be securely transmitted to port 25 on the server (which is configured to relay mail which arrives from 127.0.0.1 but not from other addresses).
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