Encountering CHECK_NRPE: Error - Could not complete SSL handshake ...

My Linux Platform is CentOS 5.x.

When you encounter CHECK_NRPE: Error - Could not complete SSL handshake ... If you encounter this error when using the nagios check_nrpe plugin and the monitored server, it could be due to the following issues.
  1. You will have only an SSL problem if the SSL version used by the check_nrpe and the NRPE daemon are incompatible
  2. Access permission for nrpe.cfg on the monitored server is blocking access. It should have read access rw_r__r__
  3. Permission error within the  /etc/nagios/nrpe.cfg file. 
    allowed_hosts=127.0.0.1,192.168.x.x
  4. You will also receive the error if the Nagios Server cannot access the NRPE serice at all through the xinetd.d service. Check the /etc/xinetd.d/nrpe service

    {
    ....
    user = nagios
    group = nagios
    server = /usr/sbin/nrpe
    server_args = -c /etc/nagios/nrpe.cfg --inetd
    log_on_failure += USERID
    disable = no
    only_from = 127.0.0.1,192.168.x.x
    }
  5. If all else fail, check the /var/log/messages 
    # grep nrpe /var/log/messages
Once successful, if you do a ./check_nrpe
# cd /usr/lib64/nagios/plugins
# ./check_nrpe -H monitored_server, 
NRPE v2.12
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