FrontDoor
FrontDoor was one of the most popular mailers in the FidoNet-compatible networks in the 1990s acting as the physical representation of the written network node connection and mail handling standards. It was a DOS-based shareware written by Joaquim Homrighausen (alias JoHo). The FrontDoor system contained a Mailer, an Editor, a Terminal, a serial port device driver and configuration utilities.