iptables is a mechanism in Linux kernel for port forwarding, NAT, firewalls etc. In Linux distros, such as Fedora, the iptables is configured to be as a “strict” firewall that opens a limited know ports, such as 22 for SSH. However, in some network environment, such as a private cluster, the nodes are trusted and
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Author: Eric Ma
Eric is a systems guy. Eric is interested in building high-performance and scalable distributed systems and related technologies. The views or opinions expressed here are solely Eric's own and do not necessarily represent those of any third parties.Installing Fedora 17 PV Domain-U on Xen with PXE Booting
Posted onAn introduction to the general method of installing Domain-U on Xen is introduced here: Setting Up Stable Xen DomU with Fedora: Unmodified Fedora 12 on top of Xenified Fedora 12 Dom0 with Xen (this is a general introduction, some details are changed, such as ‘xl’ replacing ‘xm’, LVM backing the disk for higher performance. But
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How to Set Default Entry in Grub2 and Grub
Posted onLinux booting is usually controlled by Grub or the new Grub2. Setting the default booting entry is a frequent operations. Here, we introduce how to set the default entry in Grub2 and Grub. Setting the default booting entry in grub2 Note1: With some version of grub2, the grub2-set-default method and the script below may not
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How to Install Xen on Fedora as Domain-0 (Fedora 17)
Posted onThe new development of Xen and Linux kernel make it easy to install Xen on Fedora as the Domain-0 now. This post uses Fedora 17 as an example platform to introduce how to set up Domain-0 on Fedora Linux. Compared to our old method (https://www.systutorials.com/setting-up-stable-xen-dom0-with-fedora-xen-3-4-3-with-xenified-linux-kernel-2-6-32-13-in-fedora-12/) which requires manually compiled Xen and patched kernel, the current
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Quickly Copying Text to a File
Posted onCopying some text to a new file is a common operation on Linux. I usually do this by opening the file with ‘vim’, pasting the text in ‘vim’, and then saving the file. I learned a more efficient and quicker way from my advisor during one discussion with him when I show him some results.
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Changing MTU to Make WiFi Faster on Linux
Posted onI experienced very slow WiFi network on Linux, while my iPhone seems surf the Internet quit fast. I pinged a site and the RTT is more than 1000ms! There must be something wrong with my Linux configuration. I tried to change the MTU from “Automatic” to “1400” on my Linux box. Surprisingly, it fix the
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How to Install MS Office 2007 on Linux using Wine
Posted onAs a Linux user, I must keep a copy of Windows. One reason is that I should edit MS Office files, such as .doc, .ppt, .xls and .xml (office 2003 xml format) required by, created by or for other using Windows. Wine worked for me with Office 2003 ever but has this or that problem.
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How to Format (Erase) DVD+RW / DVD-RW Disks in Linux
Posted onThis post introduces how to erase / blank / format a DVM+RW media on Linux in the command line. First, you need to find out the device of the DVD/CD+RW drive on your Linux box. For example, on my box with Linux 3.3.4 kernel, my DVD/CD+RW drive is /dev/sr0. You can also see what the
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Finding the Number of Files (inodes) in a Directory on Linux
Posted onOn Linux, to find the number of files (inodes) in a directory: $ find ./ | wc -l to find the number of files (not directories) in a directory: $ find ./ -type f | wc -l to find the number of directories in a directory: $ find ./ -type d | wc -l
How to Flush Linux File System Caches
Posted onWe may drop the file system caches on Linux to free up memory for applications. Kernels 2.6.16 and newer provide a mechanism via the /proc/ to make the kernel drop the page cache and/or inode and dentry caches on command. We can use this mechanism to free up the memory. However, this is a non-destructive
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How to Disable IPv6 on Linux
Posted onIPv6 is enabled by default on most Linux distros. However, IPv6 is not used for some situations for most of time and it may cause troubles and requires effort to protect the network and ensure the security. This post introduces how to disable IPv6 support on Linux (newer modern Kernel versions). First, add these lines
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Wireless, 3G and 2G Network Speed
Posted onI get wireless, 3G and 2G network connection via my iPhone. I tested the network speed of a wireless, 3G and 2G network possible from my iPhone using the App from OFCA. Wifi of sMobileNet network in HKUST: 25604 kbps: 3G network from a carrier in Hong Kong: 2776 kbps: 2G network from a carrier
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Setting Taping Touchpad As Left Button Click in KDE
Posted onSetting taping the touchpad as left button click in KDE is introduced in this post. The software package needed: # yum install kcm_touchpad A picture that is worth a thousand words: (In the “Input Devices” of KDE System Settings.)
How to Use MPlayer to Play DVD Directories / ISO Files / Disks
Posted onMPlayer is a universal (nearly) movie/music player on Linux and many more systems. It’s also my favourite player and MPlayer plays movie or music files in any format that I drop to it. Now, let’s take a look at how to use MPlayer play DVD. MPlayer plays “DVD” in many formats: DVD disks, ISO files,
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Vim as KMail’s External Editor
Posted onVim is my favourite text editor and I also prefer to use Vim to compose Email. I ever used Vim as Thunderbird’s External editor with the help of plugin. I started to use KMail as my email client on KDE and I find it is not hard to configure KMail to use Vim as email
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Online Tutorials for Linux Beginners
Posted onThis post compiles a list of tutorials on the Internet for Linux beginners. Linux beginners usually get headache from the “seemed” complexity of the Linux operation system. But once they get into the gate and get familiar with Linux, they will love it. UNIX Tutorial for Beginners “A beginners guide to the Unix and Linux
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How to Change Hostname of Fedora Linux
Posted onDifferent Linux distros have different method to set the hostname. On Fedora Linux, it is quite simple. On newer Fedora releases At least from Fedora 19 (sorry, no sure the exact earliest version): You need to edit the file /etc/hostname which just contains the hostname. On older Fedora releases Sorry, I do not know the
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Extending a LVM Volume Group
Posted onWe introduced how to create a LVM group with two hard disk partitions, which the LVM group can be used for [[setting-up-lvm-backed-xen-domu|installing LVM backed Xen DomUs]]. The LVM volume can have large capacity from several hard disks. However, we may use all the disk space after some time and we may need to extend the
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How to SSH to Linux Hosts for Beginners
Posted onThis is a simple tutorial for beginners to SSH to a Linux host. This is quite easy with the easy-to-use software freely available but the beginners need a tutorials to start with. Hence, I write this tutorial about how to ssh to a Linux host. This tutorial is for users on Windows. 1. Download a
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How to Convert JPG Images to EPS
Posted onI write a lot latex documents and most of the documents have images in it. Latex deals EPS very well, while sometimes we need to add JPG / PNG images to it. I find converting the JPG images to EPS ones is the most convenient way to embed JPG images to latex documents. On Linux,
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