nixCraft » Debian Linux http://www.cyberciti.biz/tips This is a Linux sys admin journal by Vivek about sys admin work, Linux tips & tricks, hacks, news and more. Fri, 03 Feb 2012 22:45:35 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 30 Best Sources For Linux / *BSD / Unix Documentation On the Webhttp://www.cyberciti.biz/tips/linux-unix-bsd-documentations.html http://www.cyberciti.biz/tips/linux-unix-bsd-documentations.html#comments Wed, 21 Dec 2011 20:11:40 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=8323 Man pages are written by sys-admin and developers for IT techs, and are intended more as a reference than as a how to. Man pages are very useful for people who are already familiar with Linux, Unix, and BSD operating systems. Use man pages when you just need to know the syntax for particular commands or configuration file, but they are not helpful for new Linux users. Man pages are not good for learning something new for the first time. Here are thirty best documentation sites on the web for learning Linux and Unix like operating systems.
Dennis Ritchie and Ken Thompson working with UNIX PDP11]]> http://www.cyberciti.biz/tips/linux-unix-bsd-documentations.html/feed 23 Debian / Ubuntu Linux: Configure Network Bonding [ Teaming / Aggregating NIC ]http://www.cyberciti.biz/tips/debian-ubuntu-teaming-aggregating-multiple-network-connections.html http://www.cyberciti.biz/tips/debian-ubuntu-teaming-aggregating-multiple-network-connections.html#comments Sun, 04 Sep 2011 23:49:46 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=8008 NIC teaming is nothing but combining or aggregating multiple network connections in parallel. This is done to increase throughput, and to provide redundancy in case one of the links fails or Ethernet card fails. The Linux kernel comes with the bounding driver for aggregating multiple network interfaces into a single logical interface called bond0. In this tutorial, I will explain how to setup bonding under Debian Linux server to aggregate multiple Ethernet devices into a single link, to get higher data rates and link failover. ]]> http://www.cyberciti.biz/tips/debian-ubuntu-teaming-aggregating-multiple-network-connections.html/feed 7 Debian Linux Version 6.0.2 Releasedhttp://www.cyberciti.biz/tips/upgrade-debian-linux-to-version-6-0-2.html http://www.cyberciti.biz/tips/upgrade-debian-linux-to-version-6-0-2.html#comments Sat, 25 Jun 2011 17:53:16 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=7896 Debian Linux version 6.0.2 has been released. This update mainly adds corrections for security problems to the stable release, along with a few adjustments to serious problems. The kernel image used by the installer has been updated to incorporate a number of important and security-related fixes together with support for additional hardware.]]> http://www.cyberciti.biz/tips/upgrade-debian-linux-to-version-6-0-2.html/feed 0 Download Debian Linux 6 Squeeze ISO / CD / DVD Imageshttp://www.cyberciti.biz/tips/download-debian-6-cd-dvd-iso.html http://www.cyberciti.biz/tips/download-debian-6-cd-dvd-iso.html#comments Sun, 06 Feb 2011 11:59:22 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=7533 Debian GNU/Linux version 6.0 has been released ( jump to download ) after 24 months of constant development and available for download in various media format. Debian 6.0 is a free operating system, coming for the first time in two flavours. Alongside Debian GNU/Linux, Debian GNU/kFreeBSD is introduced with this version as a "technology preview". It also supports various processor architectures and includes the KDE, GNOME, Xfce, LXDE and other desktop environments. It also features compatibility with the FHS v2.3 and software developed for version 3.2 of the LSB. ]]> http://www.cyberciti.biz/tips/download-debian-6-cd-dvd-iso.html/feed 16 HowTo: Create sar Graphs With kSar [ Identifying Linux Bottlenecks ]http://www.cyberciti.biz/tips/identifying-linux-bottlenecks-sar-graphs-with-ksar.html http://www.cyberciti.biz/tips/identifying-linux-bottlenecks-sar-graphs-with-ksar.html#comments Tue, 15 Dec 2009 06:33:21 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=6165 The sar command collect, report, or save UNIX / Linux system activity information. It will save selected counters in the operating system to the /var/log/sa/sadd file. From the collected data, you get lots of information about your server:
  1. CPU utilization
  2. Memory paging and its utilization
  3. Network I/O, and transfer statistics
  4. Process creation activity
  5. All block devices activity
  6. Interrupts/sec etc.

sar output can be used for identifying server bottlenecks. However, analyzing information provided by sar can be difficult, so use kSar, which can take sar output and plot a nice easy to understand graph over period of time. ]]> http://www.cyberciti.biz/tips/identifying-linux-bottlenecks-sar-graphs-with-ksar.html/feed 21 Linux / Windows Application For Prevention Of RSI (Repetitive Strain Injury)http://www.cyberciti.biz/tips/repetitive-strain-injury-prevention-software.html http://www.cyberciti.biz/tips/repetitive-strain-injury-prevention-software.html#comments Wed, 04 Nov 2009 05:21:00 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=5950 workrave-image Repetitive strain injury (RSI) is occupational overuse syndrome, non-specific arm pain or work related upper limb disorder. RSI caused from overusing the hands to perform a repetitive task, such as typing, writing, or clicking a mouse. Unfortunately, most people do not understand what RSI is or how serious it can be. You can easily prevent RSI using open source software called Workrave.]]> http://www.cyberciti.biz/tips/repetitive-strain-injury-prevention-software.html/feed 14 20 Linux Server Hardening Security Tipshttp://www.cyberciti.biz/tips/linux-security.html http://www.cyberciti.biz/tips/linux-security.html#comments Fri, 30 Oct 2009 07:52:11 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=5687 Securing your Linux server is important to protect your data, intellectual property, and time, from the hands of crackers (hackers). The system administrator is responsible for security Linux box. In this first part of a Linux server security series, I will provide 20 hardening tips for default installation of Linux system.]]> http://www.cyberciti.biz/tips/linux-security.html/feed 102 Use a Linux LiveCD to Avoid Windows Malware For Netbankinghttp://www.cyberciti.biz/tips/use-linux-live-cd-usb-for-online-banking.html http://www.cyberciti.biz/tips/use-linux-live-cd-usb-for-online-banking.html#comments Thu, 15 Oct 2009 12:53:55 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=5791 Internet has revolutionized the way online users can shop and avail banking services like internet Banking from anywhere, anytime without visiting bank. But, how safe is your money with online net-banking which allows to carry out money transfer? Companies and in some case individuals lost anywhere from $10,000 to $500,000 dollars because of a single malware infection. The cyber crooks are targeting innocent MS-Windows user. If you are concerned about how best to protect yourself from this type of fraud, use Linux LiveCD for online banking and avoid Microsoft Windows at all cost.]]> http://www.cyberciti.biz/tips/use-linux-live-cd-usb-for-online-banking.html/feed 6 Celestia 3D Space Simulation Software For Linux / Windows / OS Xhttp://www.cyberciti.biz/tips/celestia-astronomy-linux-program.html http://www.cyberciti.biz/tips/celestia-astronomy-linux-program.html#comments Wed, 30 Sep 2009 23:20:07 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=5745 celestia-europe-Io-jupiter Celestia is a real-time visual space simulation astronomy program. It is a cross platform, open source software and released under the GNU General Public License. NASA and ESA have used Celestia in their educational and for interfacing to trajectory analysis software. It allows users to travel through an extensive universe, modeled after reality, at any speed, in any direction and at any time in history. Celestia displays and interacts with objects ranging in scale from artificial satellites to entire galaxies in three dimensions using OpenGL. It is a perfect software for astronomer, educator, student, and teacher for astronomy purpose.]]> http://www.cyberciti.biz/tips/celestia-astronomy-linux-program.html/feed 11 BIND 9 Dynamic Update DoS Security Updatehttp://www.cyberciti.biz/tips/bind-dynamic-update-dos.html http://www.cyberciti.biz/tips/bind-dynamic-update-dos.html#comments Wed, 29 Jul 2009 15:47:12 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=5570 BIND 9 is an implementation of the Domain Name System (DNS) protocols. named daemon is an Internet Domain Name Server for UNIX like operating systems. Dynamic update messages may be used to update records in a master zone on a nameserver. When named receives a specially crafted dynamic update message an internal assertion check is triggered which causes named to exit. An attacker which can send DNS requests to a nameserver can cause it to exit, thus creating a Denial of Service situation. configuring named to ignore dynamic updates is NOT sufficient to protect it from this vulnerability. This exploit is public. Please upgrade immediately.]]> http://www.cyberciti.biz/tips/bind-dynamic-update-dos.html/feed 7 Top 20 OpenSSH Server Best Security Practiceshttp://www.cyberciti.biz/tips/linux-unix-bsd-openssh-server-best-practices.html http://www.cyberciti.biz/tips/linux-unix-bsd-openssh-server-best-practices.html#comments Fri, 24 Jul 2009 21:49:43 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=5489 Don't tell anyone that I'm free OpenSSH is the implementation of the SSH protocol. OpenSSH is recommended for remote login, making backups, remote file transfer via scp or sftp, and much more. SSH is perfect to keep confidentiality and integrity for data exchanged between two networks and systems. However, the main advantage is server authentication, through the use of public key cryptography. From time to time there are rumors about OpenSSH zero day exploit. Here are a few things you need to tweak in order to improve OpenSSH server security.]]> http://www.cyberciti.biz/tips/linux-unix-bsd-openssh-server-best-practices.html/feed 106 20 Linux System Monitoring Tools Every SysAdmin Should Knowhttp://www.cyberciti.biz/tips/top-linux-monitoring-tools.html http://www.cyberciti.biz/tips/top-linux-monitoring-tools.html#comments Sat, 27 Jun 2009 02:26:39 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4934 Need to monitor Linux server performance? Try these built-in command and a few add-on tools. Most Linux distributions are equipped with tons of monitoring. These tools provide metrics which can be used to get information about system activities. You can use these tools to find the possible causes of a performance problem. The commands discussed below are some of the most basic commands when it comes to system analysis and debugging server issues such as:
  1. Finding out bottlenecks.
  2. Disk (storage) bottlenecks.
  3. CPU and memory bottlenecks.
  4. Network bottlenecks.
]]> http://www.cyberciti.biz/tips/top-linux-monitoring-tools.html/feed 265 Linux Find Out If PCI Hardware Supported or Not In The Current Running Kernelhttp://www.cyberciti.biz/tips/linux-find-supported-pci-hardware-drivers.html http://www.cyberciti.biz/tips/linux-find-supported-pci-hardware-drivers.html#comments Wed, 03 Jun 2009 15:05:04 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4971 From my mailbag:
How do I find out if a given PCI hardware is supported of by the current CentOS / Debian / RHEL / Fedora Linux kernel?
You can easily find out find out if a given piece of PCI hardware such as RAID, network, sound, graphics card is supported or not by the current Linux kernel using the following utilities under any Linux distributions.]]> http://www.cyberciti.biz/tips/linux-find-supported-pci-hardware-drivers.html/feed 9 Linux x86_64: Detecting Hardware Errorshttp://www.cyberciti.biz/tips/linux-server-predicting-hardware-failure.html http://www.cyberciti.biz/tips/linux-server-predicting-hardware-failure.html#comments Tue, 02 Jun 2009 21:54:58 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4951 The Blue Screen of Death (BSoD) is used for the error screen displayed by Microsoft Windows, after encountering a critical system. Linux / UNIX like operating system may get a kernel panic. It is just like BSoD. The BSoD and a kernel panic generated using a Machine Check Exception (MCE). MCE is nothing but feature of AMD / Intel 64 bit systems which is used to detect an unrecoverable hardware problem.

Program such mcelog decodes machine check events (hardware errors) on x86-64 machines running a 64-bit Linux kernel. It should be run regularly as a cron job on any x86-64 Linux system. This is useful for predicting server hardware failure before actual server crash.]]> http://www.cyberciti.biz/tips/linux-server-predicting-hardware-failure.html/feed 6 ss: Display Linux TCP / UDP Network and Socket Informationhttp://www.cyberciti.biz/tips/linux-investigate-sockets-network-connections.html http://www.cyberciti.biz/tips/linux-investigate-sockets-network-connections.html#comments Tue, 02 Jun 2009 12:56:31 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4940 The ss command is used to dump socket statistics. It allows showing information similar to netstat command. It can display more TCP and state information than other tools. It is a new, incredibly useful and faster (as compare to netstat) tool for tracking TCP connections and sockets. SS can provide information about:
  • All TCP sockets.
  • All UDP sockets.
  • All established ssh / ftp / http / https connections.
  • All local processes connected to X server.
  • All the tcp sockets in state FIN-WAIT-1 and much more.
]]> http://www.cyberciti.biz/tips/linux-investigate-sockets-network-connections.html/feed 9 Linux Kernel Security (SELinux vs AppArmor vs Grsecurity)http://www.cyberciti.biz/tips/selinux-vs-apparmor-vs-grsecurity.html http://www.cyberciti.biz/tips/selinux-vs-apparmor-vs-grsecurity.html#comments Wed, 27 May 2009 22:29:17 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4903 Linux kernel is the central component of Linux operating systems. It is responsible for managing the system's resources, the communication between hardware and software and security. Kernel play a critical role in supporting security at higher levels. Unfortunately, stock kernel is not secured out of box. There are some important Linux kernel patches to secure your box. They differ significantly in how they are administered and how they integrate into the system. They also allow for easy control of access between processes and objects, processes and other processes, and objects and other objects. The following pros and cons list is based upon my personal experience. ]]> http://www.cyberciti.biz/tips/selinux-vs-apparmor-vs-grsecurity.html/feed 14 Lighttpd mod_rrdtool: Monitor The Load, Requests Per Seconds and Traffichttp://www.cyberciti.biz/tips/rhel-fedora-centos-debian-ubuntu-lighttpd-mod_rrdtool.html http://www.cyberciti.biz/tips/rhel-fedora-centos-debian-ubuntu-lighttpd-mod_rrdtool.html#comments Sat, 23 May 2009 09:53:22 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4878 The round-robin database tool aims to handle time-series data like network bandwidth, temperatures, CPU load etc. The data gets stored in round-robin database so that system storage footprint remains constant over time. Lighttpd comes with mod_rrdtool to monitor the server load and other details. This is useful for debugging and tuning lighttpd / fastcgi server performance. ]]> http://www.cyberciti.biz/tips/rhel-fedora-centos-debian-ubuntu-lighttpd-mod_rrdtool.html/feed 8 How To Use Gmail Account To Relay Email From a Shell Prompthttp://www.cyberciti.biz/tips/linux-use-gmail-as-a-smarthost.html http://www.cyberciti.biz/tips/linux-use-gmail-as-a-smarthost.html#comments Sun, 05 Apr 2009 19:29:28 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4596 Usually, you do not need to setup an email server under Linux desktop operating system. Most GUI email clients (such as Thunderbird) supports Gmail POP3 and IMAP configurations. But, how do you send mail via the standard or /usr/bin/mail user agents or a shell script? Programs such as sendmail / postfix / exim can be configured as a gmail smarthost but they are largely overkill for this use. ]]> http://www.cyberciti.biz/tips/linux-use-gmail-as-a-smarthost.html/feed 42 Lighttpd Install mod_geoip For Country / City Level Geo Targetinghttp://www.cyberciti.biz/tips/linux-lighttpd-install-mod_geoip-tutorial.html http://www.cyberciti.biz/tips/linux-lighttpd-install-mod_geoip-tutorial.html#comments Sun, 29 Mar 2009 04:35:28 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4567 Geolocation software is used to get the geographic location of visitor using IP address. You can determine country, organization and guess visitors location. This is useful for:

a] Fraud detection.

b] Geo marketing and ad serving.

c] Target content.

d] Spam fighting.

e] And much more.

mod_geoip is a Lighttpd module for fast ip/location lookups. In this tutorial you will learn about mod_geoip installation and php server side examples to determine visitors country. ]]> http://www.cyberciti.biz/tips/linux-lighttpd-install-mod_geoip-tutorial.html/feed 10 Tips To Protect Linux Servers Physical Console Accesshttp://www.cyberciti.biz/tips/tips-to-protect-linux-servers-physical-console-access.html http://www.cyberciti.biz/tips/tips-to-protect-linux-servers-physical-console-access.html#comments Thu, 12 Mar 2009 19:09:31 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4490 This is an user contributed article.

Linux computer console is a physical device to operate a computer / server. Here are few steps which, if taken, make it more difficult for an attacker to quickly modify a system from its console.]]> http://www.cyberciti.biz/tips/tips-to-protect-linux-servers-physical-console-access.html/feed 19