## Register agent - Linux agent ```bash cmk-agent-ctl register --hostname <server fqdn> --server <checmk server fqdn>:<checkmk agent port> --site <checkmk site name> --user <checkmk user> ``` - Windows agent ```powershell "C:\Program Files (x86)\checkmk\service\cmk-agent-ctl.exe" register --hostname <server fqdn> --server <checmk server fqdn>:<checkmk agent port> --site <checkmk site name> --user <checkmk user> ``` ## Allow monitoring server to connect to agent - Create zone ```bash firewall-cmd --new-zone=monitoring --permanent ``` - Reload configuration ```bash firewall-cmd --reload ``` - Add source IP ```bash firewall-cmd --zone=monitoring --add-source=x.x.x.x/32 --permanent ``` - Allow port ```bash firewall-cmd --zone=monitoring --add-port=6556/tcp --permanent ``` - Reload configuration again ```bash firewall-cmd --reload ``` - Review configuration ```bash firewall-cmd --zone=monitoring --list-all ``` ## Sources [How to Enable Port for a Specific IP Address in Firewalld - Ucartz Online Pvt Ltd](https://www.ucartz.com/clients/knowledgebase/2258/How-to-Enable-Port-for-a-Specific-IP-Address-in-Firewalld.html)