Development of the ucspi-ssl package has stalled here at its original home. Fortunately others have stepped in to continue development and improve upon what came before. Please refer to the Related Software links below.




Preforking Servers

General Information

What Is ucspi-ssl?

The ucspi-ssl package contains tools for building client-server applications using SSL sockets. They conform to the UNIX Client-Server Program Interface, UCSPI.


The sslserver program listens for connections on an SSL socket and runs a program for each connection it accepts. The program environment includes variables that hold the local and remote host names, IP addresses, and port numbers. The sslserver program can limit concurrency and provide selective handling of connections based on client identity.

The sslclient program requests a connection to a TCP socket, and runs a program. The program environment includes the same variables as for sslserver.

Related Software

Alternative ucspi-ssl Packages

Scott Gifford’s ucspi-ssl.

Erwin Hoffman’s ucspi-ssl.

Git repository ucspi-ssl.

Other Packages

The original UCSPI package by D.J. Bernstein, ucspi-tcp.

A local-domain socket UCSPI package, ucspi-ipc.


Files in this package are in the public domain.

The ucspi-ssl package comes with NO WARRANTY.