Few will deny that monitoring of Cisco devices is essential part of sysadmin’s job. I personally use Nagios to track states of BGP neighbors on Cisco routers so if one of peers goes down I’ll receive a phone call from Nagios. You may have redundant… Read More »Track Cisco BGP peers using Nagios
In this post you will find top open source software for IP address management (IPAM). If you are sysadmin at organization that holds pool of IP addresses and allocates its parts to clients then you must use IP address management tools to track used, reserved, allocated… Read More »Top Open Source IP Address Management Software
A few days ago LinuxScrew website has moved to a new design and partially to a new hosting. It is still based on WordPress engine (I still think it’s the best platform for this class of websites). You are more than welcome to take a… Read More »Meet new design of LinuxScrew
Linux system monitoring is one of the most important tasks for every sysadmin: it is crucial to know everything about system including CPU load, network traffic statistics, memory consumption, logged in users, availability of disk free space or service. And it’s inevitable that something breaks… Read More »Top 5 Linux Monitoring Tools. Web Based.
Wget is an elegant command line tool for downloading files over HTTP, HTTPs or FTP. Many of us are using it to just to get or reget files (reget means continue downloading of partially-downloaded file), save web pages with all contents (known as recursive download).… Read More »Wget with Proxy
Most of Linux users are using wget from time to time, sometimes even when they don’t know about it – many GUI download managers for Linux are based on wget. Anyways wget is command line tool for downloading files over HTTP, HTTPs and FTP protocols… Read More »Wget Cookies: Download Protected Content
As any other monitoring system Nagios can produce false alarms. Usually it happens when Nagios fails to get the reply from the host being monitored during some pre-defined timeout. In order to mark service as down Nagios does three checks and if all of them… Read More »Fix socket timeouts in Nagios
Nfsen is open source sensor: it accepts netflow data from multiple netflow probes (servers, routers, vpn concentrators etc) and then visualizes it into human readable form. So using Nfsen you can see traffic statistics of every network device in your network in one place (actually Nfsen provides much more features).
By default Nfsen makes it possible to see only inbound and outbound traffic statistics but no protocol breakdown or any traffic classification. In the meantime it’s always useful to know what network applications are eating the bandwidth to understand if that fits baseline or not and take necessary actions. For example, if you’re monitoring Linux server which primary task is to host some website but in Nfsen you see that it generates 90% of SSH traffic and only 10% of web traffic then it would be reasonable idea to check if somebody is trying to brute force SSH password and stop that activity. In other words it’s better to have traffic statistics classified. In this article I’ll tell you how to enable traffic classification in Nfsen.
The term “Ubuntu” hails from South Africa and is defined as “humanity or kindness”… The meaning of this word is the whole philosophy behind the operating system named after it — Ubuntu. The company of Ubuntu believes that software should be available free of charge,… Read More »A Few Reasons to Love Ubuntu [Guest Post]
Some time ago I found it pretty useful to configure Nagios monitoring system to send me a phone call in case of some critical problem. If some mission critical application goes down at night most probably you’ll miss an e-mail or sms notifying about that… Read More »Phone call as Nagios notification