Monitoring related tutorial/FAQ

pfSense email notification when fallback WAN connection goes down

last updated August 1, 2018 in FreeBSD, Monitoring, Troubleshooting, UNIX

I have two WAN connection. The first WAN connection connects via FTTH modem. The second connection connects via 4G LTE CPE modem. I have configured fallback and load balanced dual WAN connection on my pfSense box. However, once in while the Internet connection either one of the WAN goes down. How can I tell pfSense to send an email notification when fallback (or any) WAN connection goes down? How to configure pfSense email notification when an alert happens?

How to install and use Monit on Ubuntu/Debian Linux server as process supervision tool

last updated June 25, 2017 in Debian / Ubuntu, Linux, Monitoring, Networking

How do I install and configure monit to restart services such as Nginx/Apache/OpenVPN server when failed on Debian or Ubuntu Linux?

FreeBSD Unix Find Out Which Programs Are Listening On a Given Port Number

last updated November 24, 2016 in FreeBSD, FreeBSD Jails (VPS), Monitoring, Networking, Security, Troubleshooting, UNIX

I‘m a new FreeBSD Unix system user. How can I find out the process/programs names listing on a certain port on a FreeBSD Unix systems using command line? How do I lookup the process which is currently bound to the given network port on a FreeBSD server?

Linux / Unix logtop: Realtime Log Line Rate Analyser

last updated July 23, 2014 in Debian / Ubuntu, Linux, Monitoring, Ubuntu Linux, UNIX

How can I analyze line rate taking log file as input on a Linux system? How do I find the IP flooding my Apache/Nginx/Lighttpd web-server on a Debian or Ubuntu Linux?

Linux: Keep An Eye On Your System With Glances Monitor

last updated April 1, 2017 in CentOS, Debian / Ubuntu, Linux, Monitoring, RedHat and Friends

Is there is a tool that can provide me a maximum of information (such as cpu, disk I/O, network, nfsd, memory and more) about my Linux/Unix server in a minimum of space in a terminal?

CentOS / RHEL: Install iftop To Display Bandwidth Usage Per interface By Host

last updated November 11, 2013 in CentOS, Monitoring, Networking, RedHat and Friends

I am running Red Hat Enterprise Linux on IBM based system. How do I display bandwidth usage on an interface by host in real time using command line option? How do I monitor bandwidth usage in a real time on RHEL or CentOS Linux based server? How can I install iftop utility on CentOS or RHEL server using the yum command?

CentOS / RHEL: Check If A Service Is Running Or Not

last updated December 13, 2013 in CentOS, Monitoring, RedHat and Friends

How do I find out if a service such as MySQL or Apache running on my Centos/RHEL/Fedora Linux server?

nixCraft