Like any other piece of software (and information generally), cmd5checkpw comes with NO WARRANTY. How to install: 1. Compile the program. % make 2. Install the programs and man page: # make install Now you should have an example poppasswd copied to your /etc directory and cmd5checkpw binary in your /bin directory. Now select a free user id in your system. Create that user in /etc/passwd do "chown thatuser /etc/poppasswd" , "chmod 400 /etc/poppasswd", "chown thatuser /bin/cmd5checkpw" and "chmod a+s /etc/cmd5checkpw". Of course replace "thatuser" with username of the user you have created.