ag@linux:~$

Monitoring and security

9 posts, oldest first.

  1. How to Install OpenVPN on CentOS 6. My 2014 notes on installing OpenVPN on CentOS 6 with easy-rsa 2.0 certificates and PAM login, with corrections and notes on what to use today.
  2. Common Linux Log Files and What Each One Records. A list of common files in /var/log and what they contain, with the Red Hat vs Debian/Ubuntu differences and how to read logs with journalctl today.
  3. Install Nagios on CentOS: Users, Web Login, Alerts and Checks. A fuller Nagios Core source install on CentOS: nagios user and nagcmd group, web interface login, plugins, alert email address and a config check.
  4. Install Nagios Core 3 and Plugins on CentOS 6: Quick Steps. A short command list for building Nagios Core 3.4.4 and the Nagios plugins from source on CentOS 6, then logging in to the web interface.
  5. Install Zabbix from Source on CentOS 6.3. My steps for compiling Zabbix server and agent on CentOS 6.3, creating its MySQL database and copying the PHP web frontend into Apache.
  6. Check Running Processes, Login History, Services and Open Ports. Quick commands to see what a Linux server is doing: ps aux for processes, last for login history and netstat or ss for listening ports and services.
  7. Configure OSSEC Email Alerts and the Alert Level. How to turn on OSSEC email notifications in ossec.conf, set the recipient, SMTP server and sender, choose the minimum alert level and restart OSSEC.
  8. Set Up an SSL Certificate on a CentOS Apache Web Server. Creating a key, CSR and self-signed certificate with OpenSSL, adding them to Apache mod_ssl on CentOS, and redirecting HTTP to HTTPS.
  9. Opening Firewall Ports with iptables. Opening ports 80, 110 and 143 by editing /etc/sysconfig/iptables, restarting the service and checking the rules, plus firewalld and ufw equivalents.