couriertls(1) on Linux
The text 0d28c47c03e4, as Debian 10 (Buster) shipped it.
the Courier mail server TLS/SSL protocol wrapper
Flags it lists
-
-host -
-localfd -
-port -
-printx509 -
-protocol -
-remotefd -
-server -
-statusfd -
-tcpd -
-user -
-verify