D. J. Bernstein
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How to install checkpassword

Like any other piece of software (and information generally), checkpassword comes with NO WARRANTY.

System requirements

checkpassword works only under UNIX.


Download the checkpassword package. The latest published checkpassword package is checkpassword-0.90.tar.gz.

Unpack the checkpassword package:

     gunzip checkpassword-0.90.tar
     tar -xf checkpassword-0.90.tar
     cd checkpassword-0.90

Compile the checkpassword program:


As root, install /bin/checkpassword:

     make setup check
Finally, send me the portability notes created by the compilation process:
     ( echo 'First M. Last'; cat `cat SYSDEPS` ) \
     | mail djb-sysdeps@cr.yp.to
Replace First M. Last with your name.


The following tests assume that you have already installed qmail.

Simulate a failed POP login:

     # /var/qmail/bin/qmail-popup blah /bin/checkpassword pwd
     +OK <...@blah>
     user Frodo
     pass Friend
     -ERR authorization failed

Simulate a successful POP login, using a correct account name and password instead of Frodo and Friend. You should see the account's home directory.

Simulate a successful POP login again, with id instead of pwd. You should see the account's uid and gid.