Nagios Client on Rocky Linux 9.5 Non-FIPS with EPEL Packages Setup

  • Similarly I went through the same steps as before.
  • I stopped at the “* Ensured that FIPS mode was enabled:” stage.
  • Enabled the EPEL repo: 
    dnf config-manager --set-enabled powertools
dnf install epel-release
  • Installed the nagios-plugins-all package: 
    dnf install -y nagios-plugins-all
  • Installed nagios-plugins-nrpe: 
    dnf install -y nagios-plugins-nrpe
  • Installed the nrpe plugin: 
    dnf install -y nrpe
  • Version of nrpe installed: 
    nrpe -V
NRPE - Nagios Remote Plugin Executor
Version: 4.1.2
  • I then continued on from the “Configured the NRPE plugin’s configuration file at /usr/local/nagios/etc/nrpe.cfg and added the address of my Nagios server:” point. The only change was that now the nrpe.cfg file was located at /etc/nagios/nrpe.cfg: 
    sed -i 's/allowed_hosts=127.0.0.1,::1/allowed_hosts=127.0.0.1,10.25.96.5/' /etc/nagios/nrpe.cfg
  • Started and enabled the nrpe service: 
    systemctl enable --now nrpe
  • Observed from systemctl status nrpe that connections were being listened for: ``` systemctl status nrpe ● nrpe.service - Nagios Remote Plugin Executor Loaded: loaded (/usr/lib/systemd/system/nrpe.service; enabled; vendor preset: disabled) Active: active (running) since Wed 2025-01-22 05:50:25 UTC; 3s ago Docs: http://www.nagios.org/documentation Main PID: 12709 (nrpe) Tasks: 1 (limit: 48983) Memory: 708.0K CGroup: /system.slice/nrpe.service └─12709 /usr/sbin/nrpe -c /etc/nagios/nrpe.cfg -f

Jan 22 05:50:25 rocky-linux-810-non-fips-nagios-client systemd[1]: Started Nagios Remote Plugin Executor. Jan 22 05:50:25 rocky-linux-810-non-fips-nagios-client nrpe[12709]: Starting up daemon Jan 22 05:50:25 rocky-linux-810-non-fips-nagios-client nrpe[12709]: Server listening on 0.0.0.0 port 5666. Jan 22 05:50:25 rocky-linux-810-non-fips-nagios-client nrpe[12709]: Server listening on :: port 5666. Jan 22 05:50:25 rocky-linux-810-non-fips-nagios-client nrpe[12709]: Listening for connections on port 5666 Jan 22 05:50:25 rocky-linux-810-non-fips-nagios-client nrpe[12709]: Allowing connections from: 127.0.0.1,10.25.96.5

* The same from `netstat -at | grep nrpe`:

netstat -at | grep nrpe tcp 0 0 0.0.0.0:nrpe 0.0.0.0:* LISTEN
tcp6 0 0 [::]:nrpe [::]:* LISTEN

* I opened the appropriate port in my firewall:

firewall-cmd –zone=public –add-port=5666/tcp –permanent firewall-cmd –reload

* Disabled `SELinux`:

setenforce 0 sed -i ‘s/SELINUX=enforcing/SELINUX=permissive/’ /etc/selinux/config

* Allowed the `nagios` server to access the client:

sed -i ‘s/allowed_hosts=127.0.0.1,::1/allowed_hosts=127.0.0.1,10.55.96.5/’ /etc/nagios/nrpe.cfg

* Restarted the `nrpe` service:

systemctl restart nrpe

* `check_nrpe` returns the expected result:

/usr/lib64/nagios/plugins/check_nrpe -H 127.0.0.1 NRPE v4.1.2 ```

Updated: