Greetings: If you want the purple grape pin for the explorers' club like Russel received, you will experiment more ;-)
cd /var/ossec/etc cp -p client.keys client.keys.backup vi client.keys # remove clobbered entries leaving zero blank lines /var/ossec/bin/ossec-control restart sleep 3 /var/ossec/bin/agent_control -l Daniel, or another ossec developer would know more as to why those entries are kept and if they are needed; but doing the above on our own server appeared to cause no problems. Thank you.
