gMFSK is a multimode HF terminal program that can send and receive many digital conversational modes typically used by radio amateurs on HF. It uses the computer soundcard to interface to an SSB capable transceiver. All digital signal processing is done in the main CPU so any soundcard should work.
ZMailer is an internet message transfer agent. It is intended for gateways or mail servers or other large site environments that have extreme demands on the abilities of the mailer. It was motivated by the problems of the Sendmail design in such situations. It is intended and designed as a multi-protocol mailer. The only protocol supported in this distribution is RFC822 (and variations).