Installing NRPE

    1. Refresh the repository: 
      sudo apt-get update
    2. Install the dependencies: 
      sudo apt-get install autoconf automake gcc libc6 libmcrypt-dev make libssl-dev wget openssl -y
    3. Change the directory to your home directory: 
      cd ~
    4. Download the nrpe 4 source codes: 
      wget https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe-4.0.3/nrpe-4.0.3.tar.gz
    5. Extract the downloaded source codes: 
      tar xvf nrpe-4.0.3.tar.gz
    6. Change to the directory of the newly extracted source codes: 
      cd nrpe-4.0.3
    7. Run the configure script that enables the command arguments for clients and uses ssl library: 
      sudo ./configure --enable-command-args --with-ssl-lib=/usr/lib/x86_64-linux-gnu/
    8. Compile the source codes: 
      sudo make all
    9. Install the nagios user and group: 
      sudo make install-groups-users
    10. Install both NRPE daemon and check_nrpe plugin: 
      sudo make install
    11. Install the nrpe config file (i.e. /usr/local/nagios/etc/nrpe.cfg): 
      sudo make install-config
    12. Install the init script: 
      sudo make install-init
    13. Enable the nrpe daemon: 
      sudo systemctl enable nrpe.service
    14. Update allowed_hosts field in the /usr/local/nagios/etc/nrpe.cfg file: to include your nagios server address (e.g. your nagios server address is 10.0.0.174 the allowed hosts is as follows): 
      allowed_hosts=127.0.0.1,::1,10.0.0.174
    15. Update the dont_blame_nrpe field: to 1 on the same configuration file to allow your clients to specify arguments: 
      dont_blame_nrpe=1
    16. Start the nrpe daemon: 
      sudo systemctl start nrpe.service

      The NRPE service is listening with the port 5666 by default.

Testing The NRPE Plugin

/usr/local/nagios/libexec/check_nrpe -H localhost

Expect to see the version of NRPE daemon

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