Free internet monitoring tools software for linux

Cimon is Perl program wich monitors the load (memory and CPU) on Cisco routers using SNMP, and generates graphics with statistics using rrdtool. Its good for information about your routers health.

It monitors and displays the cpu 5 minutes utilization in percents and free+used Processor memory. The I/O memory(usualy 2 MB) or Fast on high end routers is being monitored too, but there isnt graphic for it. Cimon is good source for information about your routers health. From version 0.2 cimon can do ip accounting using the cisco ip accounting feature.
The logfiles that it generates as the rrd files needed for the graphics are fully compatible with those produced by sasacct (SASs accounting statistics). So you can use its cgi interface also its posibility to generate graphics on demand or on a user defined interval (via crontab and -g option).

Remote Monitoring Agent (RMA in short) is an auxiliary application for HostMonitor. Enterprise license for Advanced Host Monitor already includes license for 10 installations of the agent. Holders of a Lite, Standard or Professional licenses may buy an additional license for Remote Monitoring Agent separately.
HostMonitor 4.0+ can monitor remote networks using Remote Monitoring Agents (RMA). RMA is small application that accepts requests from HostMonitor, performs test and provides information about test result back to HostMonitor.
Why you may need RMA? Here are just several reasons:
RMA increases security of the network. When you have to run the tests such as CPU Usage test or Performance Counters tests on a remote Windows system, HostMonitor must be able to log in to that system with administrators privileges. Instead you may now use an agent installed on that remote system. In this case HostMonitor will not have to log on to that system at all. HostMonitor needs just one TCP port to communicate with the RMA agent (by default it uses #1055 port, however you may set an agent to use any other port).
Remote Monitoring Agent is also a very useful tool when you have to monitor two (or many) separated networks (connected through Internet). In this case installing just one instance of RMA behind the firewall in network "A" will allow to monitor entire network "A" using the HostMonitor located in the network "B" with just one open TCP port.
RMA decreases the network traffic. E.g. frequent use of "File Integrity" or "Compare Files" tests in an array of remote systems may apply significant load on the network. The more and the bigger files you test the more traffic increase you get. RMA runs locally and sends only the test results to the HostMonitor thus decreasing the amount of network traffic.
Remote Monitoring Agent simplifies network administration. You no longer need to share local drives/folders to perform tests such as File Integrity, Folder/File Size, File Availability, Count Files, etc
RMA for Linux / BSD / Solaris allows you to perform tests that HostMonitor cannot perform. For example HostMonitor cannot monitor processes that are running on Linux systems. RMA can do that.
Main features:
- All traffic between Remote Monitoring Agents and HostMonitor is encrypted.
- It is possible to customize the list of enabled tests for each of the agents (e.g. living only Count Files and UNC tests only).
- You can restrict incoming TCP connections with the list of acceptable addresses.
- With RMA Manager you may configure, restart and even upgrade agent(s) remotely.

Postfix SMTP Monitoring Solution is a set of three Perl CGI scripts used to monitor the SMTP queue, allowing the deletion of messages that for one reason or another become "stuck" in the queue.

I needed a web-based solution to monitor my Postfix SMTP relay, which enabled me to remove messages that become "stuck" in the queue. I wrote three simple Perl scripts, and used Sudo to give me the desired functionality.

I am uploading these scripts in case they are useful to others. Assuming you have Apache configured correctly on your Postfix server, it should be as easy as placing the three .cgi files into your webservers cgi-bin directory, and making the appropriate modifications to your /etc/sudoers file (see the README contained in the tarball).

Orange Monitor is a system monitoring theme for SuperKaramba.
Main features:
- CPU Load and Temperature (mbmon)
- Used RAM
- Used Space on hda and hda2 (customizable)
- Bandwidth Spent (bars are customizable , Incoming gets full @ 1GB and Outgoing @ 256MB by default)
- XMMS Controls (xmmsctrl)
Inspired on:
- Yaxay Skin for Winamp3
- Pod Icons for LiquidWeather karamba
- SystemTux Karamba