Check Microsoft’s Exchange 200x OWA (Outlook Web Access) service (e.g. https://mail.domain.com/exchange) to make sure that it is running properly.

[edit] localhost.cfg

#taken from CentOS 4
define service{
        use                             local-service
        host_name                       mail.yourdomain.com
        service_description             OWA_https_check
        check_command                   check_http! --ssl -u /exchange
        }

[edit] commands.cfg

#taken from CentOS 4
define command{
        command_name    check_http
        command_line    $USER1$/check_http -H $HOSTADDRESS$
        }