📦 Installation Command
apt install nagios4 nagios-plugins nagios-nrpe-plugin
Nagios Monitoring Port & Configuration
nagios systemctl: nagios4Industry-standard IT infrastructure monitoring. Monitors hosts, services, and network.
🔌 Default Ports
80
tcp
Web interface (via Apache)
5666
tcp
NRPE agent
⚙️ Configuration Files
/etc/nagios4/nagios.cfg/etc/nagios4/cgi.cfg/etc/nagios4/objects/contacts.cfg/etc/nagios4/objects/localhost.cfg
📂 Default Directories
- config:
/etc/nagios4 - data:
/var/lib/nagios4 - logs:
/var/log/nagios4 - plugins:
/usr/lib/nagios/plugins - objects:
/etc/nagios4/objects
🔐 Default Credentials
Username:nagiosadmin
Password:Set during install
💡 htpasswd -c /etc/nagios4/htpasswd.users nagiosadmin to set/reset
📌 Dependencies
⚠️ Conflicts
✅ Works With
🛡️ Security Notes
Secure web interface with strong password, restrict access by IP, use NRPE over SSL
❓ Frequently Asked Questions
What port does Nagios use?
Nagios NRPE agent uses port 5666. Web interface runs on HTTP port 80.
What is NRPE?
NRPE (Nagios Remote Plugin Executor) allows remote execution of plugins on monitored hosts.
Where is Nagios config?
Config at /etc/nagios/nagios.cfg with objects in /etc/nagios/objects/.