check_certexp is a Nagios plugin for checking the number of days left until a
certificate expires. The check is done via an SSL connection (STARTTLS
mechanisms are not supported). The plugin is written in Perl, should work with
the embedded Perl interpreter (not tested though) and requires Net::SSLeay and
Date::Manip to be installed on the Nagios host.

WWW: http://www.jhweiss.de/software/nagios.html