Certwatch checks for Apache certificates which are due to expire. By default on Red Hat / Centos there is a cron job in /etc/cron.daily which runs and sends its output to root. To configure it:

vi /etc/sysconfig/httpd

Add a line such as:

CERTWATCH_OPTS=”–period 30 –address my.user@domain.tld”

It is also possible to switch it off with: