At Reverse Polarity, we have been installing, configuring, managing and supporting m0n0wall firewalls since we found the m0n0wall firewall project in 2005.

From the m0n0wall website: "m0n0wall is a project aimed at creating a complete, embedded firewall software package that, when used together with an embedded PC, provides all the important features of commercial firewall boxes (including ease of use) at a fraction of the price (free software)."

With so many of our managed m0n0wall firewalls installed it is only sensible to assume that we would know the status (including version, platform and uptime) of them. That would be a good assumption. :)

For quite some time now, we have been monitoring our clients' networks and servers with Xymon so it only makes sense that we would use Xymon to monitor our clients' firewalls as well.

We have recently posted our xymon_m0n0CFG.rb script which reports back to our Xymon server the version, platform, uptime, last config change, and notes fields of each of our managed m0n0wall firewalls. In addition to simply reporting back these informational fields, the script will also set a yellow alert if a firewall has been up for less than 24 hours, or if the configuration has been recently modified.

Instructions for installing the xymon_m0n0CFG.rb script, as well as the latest version of the script may be found HERE.

posted from my Nokia N900

For several years now, we have been installing the open-source program NUT (Network UPS Tools) to monitor our UPSes and our clients UPSes to safely shut down servers during extended power outages.

With NUT we can rest assured that servers will not just have their power killed when their UPS's battery dies, but instead will be told to perform an orderly shutdown before the battery is exhausted which can prevent costly issues including file corruption.

The "N" in NUT stands for NETWORK which of course means that there is a networking aspect to it. Not only is NUT capable of monitoring UPSes via serial ports and USB ports but also via SNMP when a UPS supports it.

In addition, the networking capabilities of NUT include the ability for a NUT server to monitor a UPS and tell multiple client machines that also derive their power from the monitored UPS to shutdown prior to the NUT server itself being shut down.

Isn't this enough monitoring? Well, we always say, "...just like backups you can never have too much monitoring." So we have written several scripts for the Xymon Monitoring Server to monitor, graph and alert on the AC input voltage, AC output voltage, battery charge %, battery voltage & UPS load % of UPSes managed by a NUT server.

The scripts and the instructions on how to install and configure them with a Xymon server may be found HERE.

posted from my Nokia N900

In a recent post to the Bacula mailing list, someone had asked if there was a way to alert their Nagios network monitoring server when their Bacula backup server was waiting on an operator to change a tape.

At Reverse Polarity, we have been installing and supporting Xymon for years - as far back as when it began as plug-in to the Big Brother network monitoring server.

Xymon is an open-source network monitoring program with an easy to use web interface. Since someone was asking about a Nagios plugin to monitor their Bacula server it only seemed logical that someone might want a way to monitor Bacula with a Xymon server.

As it turns out, someone DID want a Xymon monitor for Bacula - Us!

As luck would have it we had already written a Xymon script to monitor our Bacula server and alert if a backup job had failed. All our script needed was some minor additional features and some finishing touches for it to be ready to be released for others to use.

I am excited to say that the script, which is available HERE was announced on the Bacula users mailing list and the Xymon users mailing list on June 4th, 2010 and within 10 minutes was being downloaded and implemented by others!

posted from my Nokia N900

Last week I wrote about monitoring, logging, graphing and alerting on a ControlByWeb temperature module's readings. What I left out was that the module in question also has two relays.

And, if a device has relays, we should do something with them!

Since Xymon is our monitoring solution of choice I wrote a bash shell script that may be called as an alert script for Xymon to turn on, off, pulse or toggle a relay for a specific alert.

Take a look at http://www.revpol.com/xymon_cbw_relay_script to see how a Xymon monitoring server can be configured to control a ControlByWeb module's relays.

posted from my Nokia N900

Recently, while looking for a reasonably priced temperature sensor device that we could integrate into a Xymon monitoring server to monitor our server room as well as our clients' server rooms, a Google search turned up ControlByWeb.com and their 4-sensor/2-relay temperature module. It met all of our requirements.

This monitor is not only inexpensive, but it is also very simple to set up. And since the temperature readings are readily available to a web browser, it is just as easy to integrate into a Xymon monitoring server using some simple shell scripting and a great utility called "curl" to pull the state.xml web page that contains the temperature readings.

Take a look at http://www.revpol.com/xymon_cbw_temp_script to see the Xymon integration instructions and the actual bash shell script you may use to monitor, log, and graph up to four temperature reading from one of these devices.

To learn more about Xymon and some of the other Open-Source tools we use and support on our network and our clients' networks, see our System Monitoring page .

posted from my Nokia N900

Here you will find a growing list of examples where Linux and other open-source software is being used successfully in schools, municipalities and businesses all around the world.

• 10/25/09 - WhiteHouse.gov Switches from Proprietary Content Management system to Drupal
• 03/31/09 - LINUX is the 'patch' to cure Conficker worm
• 03/23/09 - SUN Microsystems CEO - "What's next for open source?"
• 02/25/09 - Dries Buytaert (Drupal Author) - On the future of open-source

Here are some PDF articles on open-source software. Click on the links below to download the article.