Hermes is a basic SMTP/POP3 server with source code. It's free to use. Read the license. Send bug reports or improvement suggestions.
emailarms
IM-Soft
JAM Software GmbH
getfreefile
Axigen - Gecad Technologies
Etype
MailEnable Pty. Ltd.
NORDOS STUDIO
BitArts Ltd
Caricature Software
Video Image Converter
Mrazo, Inc.
Business Software
EgyFirst Software, inc.
Bahrur Rahman
Aiseesoft
XYZSoftware