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The easiest way to split and merge pdf files in Ubuntu
The easiest way to split, merge or edit pdf files in Ubuntu is to use pdftk utility. This rather old (latest version was released in 2006) but still simple and powerful program can be installed in...
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How to monitor traffic at Cisco router using Linux (Netflow)
By default Cisco IOS doesn’t provide any traffic monitoring tools like iftop or iptraff available in Linux. While there are lots of proprietary solutions for this purpose including Cisco Netflow...
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How to assign range of IP addresses in Linux?
As we know Linux allows to assign almost unlimited number of IP addresses to its interfaces. Such additional IPs applied to the same NIC are known as secondary IP addresses or just secondaries. Some...
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Namebench: cross-platform DNS benchmarking tool
It was long time ago when I wrote here last time but today I’d like to share the link to an application that would be appreciated by everyone starting from Linux starter wishing to speed up his/her...
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Sendmail for virtual users with procmail, spamassassin and dovecot
Today I’d like to describe setup of sendmail that allows to establish receiving of e-mails for certain domain and sort incoming messages between virtual users. Those users must be able to fetch...
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Quick Tip: Increase port range available for applications
By default an average Linux distribution allows applications to use the following TCP port range for outgoing connections: 32,786-65,536. That’s why your system can handle up to 28,232 TCP sessions at...
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Install nfdump and nfsen netflow tools in Linux
Using nfsen it is possible to view IP traffic statistics on Linux interfaces including the graphs showing data sent and received (see the screenshot to the right) as well as historical information...
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Cisco Load Balancing with Failover setup example
There is Cisco router of 7200 series with 4 FastEthernet interfaces (FE) and 2 serial ports. It should act as load balancer and failover for LAN connected to it via one FE 1/0 interface while two...
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The Implementing Cisco IP Routing (CCNP Route 642-902). Materials for...
A few days ago I have successfully passed 642-902 exam (CCNP ROUTE v6) and would like to share the list of materials I have been using to prepare to that exam. To get prepared I was using official...
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Phone call as Nagios notification
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...
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Nfsen: Traffic Classification
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...
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Fix socket timeouts in Nagios
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...
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Wget Cookies: Download Protected Content
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...
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Wget with Proxy
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...
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PostgreSQL to File
PostgreSQL (or simply Postgres) is powerful and extremely popular database management system. It comes with easy to use tool that makes it possible to export output of any query into text file. If you...
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Top 5 Linux Monitoring Tools. Web Based.
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...
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Meet new design of LinuxScrew
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...
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Top Open Source IP Address Management Software
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...
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Track Cisco BGP peers using Nagios
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...
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Linux Mint Debian Update Pack 4 is out
The latest update of Linux Mint Debian has been rolled out today. Update pack 4 is applicable for all LMDE users and includes the following updates: Gnome 2 has been upgraded to Gnome Shell, kernel is...
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