This Howto demonstrates how to install OpenKM 5.1.9 with JRE (Jboss) on CentOS. First download JRE from the following website: http://www.oracle.com/technetwork/java/javase/downloads/jre-7u4-download-1591157.html Install JRE using the following command: yum install jre-7u4-linux-x64.rpm Next, download OpenKM using the following command: wget http://downloads.sourceforge.net/project/openkm/5.1/OpenKM-5.1.9_JBoss-4.2.3.GA.zip?r=http%3A%2F%2Fwww.openkm.com%2Fformulario%2Fdownload.php%3Faction%3DOnly%2520download&ts=1336620287&use_mirror=internode Extract the application to “/var/www/html/OpenKM” as follows: unzip ./OpenKM-5.1.9_JBoss-4.2.3.GA.zip mv jboss-4.2.3.GA /var/www/html/OpenKM Now you need...

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You can sae space on a Redhat or CentOS server by removing the cache dies from “/var/cache”. The proper way to do this is with the following command: yum clean all The “yum clean” command has other options but the “all” option will be most liberal.

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Using “getent” with Winbind, you can get extended user information from Active Directory. For example, without Winbind, getent will return user information from “/etc/passwd” only (well, by default). You can see this by checking your “/etc/nsswitch.conf” file. For some background information, here is an extract of the /etc/nsswitch.conf file that doesn’t use Winbind: passwd:...

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Running the following command will remove all email stuck (or simply in) your Postfix mail queue. postsuper -d ALL You’ll see something like the following: postsuper: Deleted: 613 messages Where i’ve just removed 613 emails from the Postfix queue.

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This HowTo explains how to install an LDAP server on a Redhat server and use if as a source of authentication and perhaps contacts. Install the LDAP server: yum install -y openldap openldap-clients openldap-servers Start the LDAP server and have it start on system boot: service slapd restart chkconfig slapd on Next install the...

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This article demonstrates how to run VNC (remote desktop tool) over an SSH (secure) session. This allows you to bypass firewalls preventing normal VNC communications (and where you cannot change the firewall to allow port 5901). In this example, the “workstation” is the computer that you’re sitting in front of. The “server” is the...

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The PlayStation 3 Media Server (PMS) allows owners of a playstation to watch movies, listen to music and browse photos that are centrally stored on a server. By using this method, other media players (such as modern TV’s, computers and purpose built media players) can use the same source of media without duplication. Installation...

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It’s never easy to compare prices between ISP’s because there are bundled prices, stand alone prices, contract prices, etc. Here is my best effort to get prices for the NBN as of this date. Having said that, i’ve ignored contract lengths but i have included my information sources for you to do more specific...

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This HowTo demonstrates the use of Selinux tools that every Linux system administrator should know. Consider reading “Getting started with Selinux” first. What are Selinux security context types? Selinux adds security contexts to files to prevent them from being used in unintended ways. For example, the file “/etc/ssh/sshd_config” has a security context type of...

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By default, the domain administrator on a Samba domain is the “root” user. The root user still must be added to the Samba user database and a password set. smbpasswd -a root You can edit the file “/etc/samba/smbusers” to give the root user aliases such as the following. In this example, the username “Administrator”...

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Knoppix 6.7 is used in this example of resetting the Windows7 Administrator user’s password and other’s passwords too if you like. Once you have the Knoppix CD ready to go, boot into the Windows7 computer using Knoppix. This will give you access to the hard disk of the Windows7 computer. Knoppix can read and...

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HyperV may require you to install some patches to get the best performance when installing Redhat/CentOS as a guest. These are the instructions to follow: Download the ISO from this URL to the target Linux system: http://www.microsoft.com/download/en/details.aspx?id=28188 Mount the ISO in Linux: mkdir /media/ISO mount -o loop LinuxIC.iso /media/ISO In the above, change LinuxIC.iso...

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This article describes how to use the auto-mounter to simplify the mounting process for frequently used remote filesystems. For example, suppose you have several workstations all mounting a common NFS share on a remote NFS server. Rather that putting an entry in each workstation’s “/etc/fstab” file and relying network connectivity to be consistent, server...

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The HyperV hypervisor from Microsoft has an interesting feature that changes the MAC address of the virtual Ethernet device(s) each time the virtual machine guest boots. Ubuntu thinks its found a new ethernet device each time the MAC address changes. Hence the incrementing ethernet name. The setting is found in the properties of the...

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This article demonstrates how to install Moodle 2.2 on a CentOS or Redhat server. Install the required packages: yum install mysql-server mysql-client php-mysql httpd php-soap php-common Download Moodle 2.2 and extract it to it’s final destination: cd /tmp wget http://download.moodle.org/download.php/direct/stable20/moodle-latest-20.tgz tar xzpf moodle-latest-20.tgz -C /var/www/html/ Now create key directories and set permissions: mkdir /var/www/moodledata...

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Linux has a nice feature called “AutoFS” which allows the system administrator of a workstation to configure remote or local file systems mounting options for all users (even non-adminsitrator) to use. New file systems to be automatically mounted are found in the “/misc” directory. Normally, without AutoFS configured and working, this directory should be...

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This article demonstrates the process of encrypting a partition using LUKS on a Redhat or CentOS system. lsmod | grep dm_crypt If there is no output from the above command, go ahead and load the modules needed – as follows. Otherwise skip this step (consider adding the following line to your “/etc/rc.local” file so...

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These are the steps to install the RHEV packages on a RHEL 6.x server. 1. Install the RHEL server. It doesn’t matter which packages were selected during installation. 2. Go to the website “http://rhn.redhat.com” and login. 3. Go to “Systems” and click on the server that you’d like to install the RHEV suite on....

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Use the following IPTables rules “/etc/sysconfig/iptables” on a Redhat/CentOS system where this system is a KVM host with KVM guests running. It’s a test script which is known to work. KVM guests often have networking troubles through the fault of the host. First backup your IPTables firewall: cp /etc/sysconfig/iptables /etc/sysconfig/iptables.backup Now apply the following...

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This article demonstrates how to create a KVM virtual machine using the “virt-install” tool. The Here is a sample command which will create a new VM with the following attributes: Machine name = MyLinuxServer Memory/RAM = 1024 MB Disk format = qcow2 Disk size = 10GB Disk path = /home/libvirt/images/MyLinuxServer.img ISO to install from...

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It’s not a matter of running YUM to install Asterisk on Redhat or CentOS. Instead, you need to compile it yourself. But don’t worry. It’s a simple process and will only take a few minutes. First make sure you have the required tools to compile Asterisk: yum install gcc gcc-c++ make openssl-devel newt-devel ncurses-devel...

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Apt-get can source from files and ISOs where the ISO has been mounted locally. This HowTo will demonstrate how to add an ISO location which also covers the local file location. First, mount the ISO: mount -o loop /home/iso/ubuntu-11.04-server-amd64.iso /media/iso Next, backup the exiting “/etc/apt/sources.list” file: cp /etc/apt/sources.list /etc/apt/sources.list.orig Now add the following line...

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On CentOS, the virsh command is used to control KVM VM guests. This article demonstrated the process of creating a snapshot of a VM guest in the qcow2 format. You can list your VM guests using the following command: virsh list --all Now create a snapshot using the name of the virtual machine derived...

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The KVM image format RAW (the default) is very basic. One feature that might be missed is the ability to Snapshot the entire virtual machine. The Qcow2 format supports snapshots. The following command will convert a KVM image from RAW to Qcow2. qemu-img convert -f raw -O qcow2 /home/libvirt/images/vmguest1.img /home/libvirt/images/vmguest1.qcow2 In the above command,...

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To find the number of physical CPU’s on the motherboard, not just cores, try the following command (you must be root to run this command): dmidecode --type 4 | grep -c Socket The output will be a number by its self. Such as “1″ or “2″ specifying the number of physical CPUs.

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This article shows a basic Asterisk 1.8.8 configuration. This article doesn’t cover installation. However, on Ubuntu, Asterisk can be installed via APT. Redhat is not so simple. In fact, in a recent CentOS 6.1 installation on which we needed Asterisk 1.8.8, it was simpler to compile from source than attempt an RPM installation. Our...

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Home networks can have multiple access points to improve coverage. High-end access points allow centralised configuration and security which is suitable for enterprise use. For home use, any access points are fine as long as they are properly configures. The goal should be to allow a laptop or other portable device to “roam” around...

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When Gnome is missing the top and bottom menu bars, you should install two extra packages: yum install -y gnome-globalmenu-common gnome-applet-globalmenu Or you can install all Gnome packages as follows (warning, it installs a lot of packages…): yum install -y gnome-* Restart your Xorg session. Either way you will gave a working Gnome environment...

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This article explains how you (the system administrator) can control servers using just your smart phone. Simply, you’ll install Webmin with a theme designed for mobile devices. Install Webmin using this HowTo: http://www.agix.com.au/blog/2011/04/installing-webmin-on-ubuntu/ Next, install the mobile theme located here: http://www.webmin.com/mobile.html Next, turn on the theme within Webmin by following these steps: 1. Log...

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This article demonstrates how to install RPM packages from a file containing a list. For example, the following command generates a list of installed RPM packages: rpm -qa The same command but output the list into a file: rpm -qa > rpm.list Now we can install the list of RPM packages based on the...

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This HowTo explains the process of reinstalling all installed packages on a Ubuntu system. Read the whole article if you don’t have Internet access and you intend to use a CD-ROM. First you need a list of currently installed packages: dpkg --get-selections > /tmp/agix.apts Now run the following to reinstall the listed packages: dpkg...

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This article explains how to configure a very basic but functional Squid web proxy. Install squid: apt-get install squid Edit the “/etc/squid/squid.conf” configuration file. The following is all that is needed: acl all src all http_port 3128 access_log /var/log/squid/access.log squid hosts_file /etc/hosts http_access allow all Restart squid: /etc/init.d/squid restart Configure web browsers (Internet Explorer,...

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Apache2 has the ability to host multiple websites using just the one Apache2 server. There are several ways to do this and we’ll focus on the “NameVirtualHost” method. Simply put, NameVirtualHost allows one web server to use one IP address to server multiple websites. Edit your first website configuration file by editing the file...

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This article explains how to monitor a Linux systems network interfaces. Install BMon using the following command: apt-get install bmon Now run “bmon” to see something similar to the following: interface: lo at www.agix.in bmon 2.0.1 # Interface RX Rate RX # TX Rate TX # www.agix.in (source: local) 0 lo 0.00B 0 0.00B...

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This article explains how to install ProFTP on a Ubuntu server and use a per-existing LDAP server for authentication. If you intend to configure the LDAP server too, consider this article which is perfect for FTP server authentication. First install proftp with the LDAP module: apt-get install proftpd-mod-ldap Uncomment the following line from the...

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Windows 7 works fine with Samba but you do need to make a registry change. Fortunately you can do this by running a “reg” patch which takes just a few seconds. Make sure you have the latest version of Samba. It doesn’t matter what password database back-end you’re using. Earlier versions of Samba do...

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The good people on the Ubuntu team have made it very easy to install Java JDK using apt-get. Simply run this command as root (or SUDO): apt-get install openjdk-6-jdk No need to modify the repositories. Note that the version may change.

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This tutorial walks through the process of extending an existing LVM to include an additional partition. The new partition can be on a new hard disk or on the same hard disk as the existing partitions that the LVM is on. See a basic introduction to LVM here: Using LVM2 On Linux In this...

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“phpmyadmin” is a tool that allows the administrator to manage MySQL databases via a web interface. Start by installing it using Apt Get: If you don’t already have a working web-server and MySQL database on this server, you should install them: apt-get install apache2 apt-get install mysql-server mysql-client Now run the following to install...

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The “logger” tool is used to send log entries to the syslog system. It’s very simple to use: logger The backups have started! The above will put the following into your systems log file “/var/log/messages”: Jun 26 21:13:12 MyServer root: The backups have started! So what does the above mean? The date and server...

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Wireless networks are great when they work. But when they don’t work, they can be simply annoying. They are difficult to troubleshoot because the cause of the problem may be your neighbors microwave, your child’s hand held game, your mobile phones Bluetooth device or your cordless phone. The problem of wireless “drop outs” is...

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This article demonstrates how to test that an SMTP server is working by using the Telnet commend. It’s also a good way to learn how SMTP works. In this example, the email subject is “This is a test” and the body of the email is “bla”. The “.” following “bla” signifies the end of...

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This article explains how to remove a NAT entry from a Cisco router that is currently in use. For example, if you try to remove an existing NAT entry that the router is currently using: no ip nat inside source static tcp 10.1.1.1 80 192.168.1.55 80 You may get the following error: Dynamic mapping...

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This article demonstrates how to change the case of a column in MySQL to lower or upper case. You need to have update access to the table. To change the case of the column “MyColumn” to lower case: UPDATE MyTables SET MyColumn=LOWER(MyColumn) To change the case of the column “MyColumn” to upper case: UPDATE...

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This article shows how to disable the cache logging feature of Squid. The “/var/log/squid/cache.log” file can grow huge depending on your logging settings within the “/etc/squid/squid.conf” file. Also, this file has very little to offer you as the administrator. To disable Squid cache logging, add the following line to the top of your “/etc/squid/squid.conf”...

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This article gives a few useful tcpdump examples. Tcpdump is a Linux network packet analyser. Using Tcpdump, the system administrator can see packets of data coming in and going out of a Linux system. Tcpdump is a great tool for network based application troubleshooting. Listening to packets on “eth0″: tcpdump -i eth0 Listening for...

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This HowTo demonstrates the Samba “Virtual Server” feature. A feature that allows a single Samba server to appear to the LAN as multiple servers. This can be usefull if two companies share the same office space and want to save money or when two companies merge. Consider this HowTo to catch up with the...

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This HowTo demonstrates how to configure dynamic DNS using Bind9 and DHCPd on Ubuntu Linux. The goal is to allow the DHCP server to update DNS zone(s) with new host leases. In this example, the DHCP and DNS servers are running on the same system. Note that this article doesn’t include reverse DNS settings....

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A regularly asked question is “how do you protect your linux machine from brute force SSH attacks?” with a seemingly infinite number of potential solutions ranging from: Setting ssh to only accept logins from specific users Setting ssh to NOT allow incoming connections from root Setting ssh to only accept incoming connections from specific...

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This HowTo explains how to recover from a Windows XP error such as “Windows could not start because the following file is missing or corrupt: WINDOWSSYSTEM32CONFIG” using Knoppix Linux. You will need a copy of Knoppix from “http://www.knoppix.de”. 1. Boot into Knoppix and choose to start a “SHELL”. 2. Mount the local hard disk...

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This HowTo explains how to manage a Windows (Samba) domain using Webmin. User management usually involves password changes, group membership changes, joining new computers to the domain and creating new user accounts. This HowTo discussed the day to day maintenance tasks and how Webmin can help. Be sure that your Linux and Samba system...

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This HowTo simply walks through the installation process for Webmin. Webmin is a web-based system administrator tool or Linux. Start by downloading the package from the Webmin website. For this tutorial, the following was used: cd ~ wget http://downloads.sourceforge.net/project/webadmin/webmin/1.540/webmin_1.540_all.deb Now install the package: dpkg -i ~/webmin_1.540_all.deb On Ubuntu 10.10, the above command completed with...

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If you’re a Windows administrator, you’ll no doubt be familiar with the Windows RDP Remote Desktop tools – otherwise known as Terminal Server. Linux administrators usually use SSH for command-line control of their Linux servers. But if desired, Linux has VNC and NX for GUI/Desktop remote controlling a Linux system. NX is available for...

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On Ubutnu, wireless networks can be configured either through a GUI or via configuration files. Use one or the other. Otherwise you will find they compete. This HowTo explains the alter. Note that you’ll be given a dynamic IP address. apt-get install wireless-tools Edit the file “/etc/network/interfaces” to include the following. Note that AGIX...

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This HowTo demonstrates how to configure Fetchmail for Ubuntu. Fetchmail is a program that will collect email from a remote email server and deliver it to the local mail system. For example, email sent to a remote email account of “andrew@remote.com” can be collected and inserted into “andrew@mymain.com”. First, install Fetchmail: apt-get install fetchmail...

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AGIX has released the new “AGIX Ping” website. You can monitor your servers and receive notifications of outages via email. You can monitor your clients servers, your servers, router or anything you can connect to on typical TCP ports. http://www.agix.com.au/ping It’s free to sign up. You can monitor up to 20 servers. This is...

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This HowTo explains how to configure Apache to serve files over the WebDav protocol. You should start with a working Apache2 configuration as documented here. Add the following to your “default” site. On our test system, the file is located at “/etc/apache2/sites-enabled/000-default”: <Directory /var/www/webdav> Options Indexes MultiViews AllowOverride None Order allow,deny allow from all...

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Small businesses can enjoy technology usually reserved for the corporates. You’re business can look impressive by spending under $35 per month for online-FAX services, Website and Email, Online Invoicing and VoIP Telephones. Here’s how: Online-FAX Service from $9.95 Per Month Some of us still need to receive or send Faxes. But it hardly seems...

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This HowTo explains a few processes to try for testing suspicions of disk errors or performance issues. The idea is to try the same test multiple times to find consistencies. Doing so may help you identify that the evenings are different to mornings or that reads are slower than writes or that the source...

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This article explains how to retrieve email addresses of users from Active Directory using the Linux command “ldapsearch”. Install the required tools: apt-get install ldap-utils The following command will report all email addresses from a specific organizational unit in Active Directory. Here are the AD details: 1. Username to authorize our query (bind’ing) =...

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