How-To: Convert a WordPress site from Multisite to Standalone install
Since wordpress 3.0, it is possible to create a network or site by using the multisite feature. It allows to manage multiple wordpress websites from a single...
Administration
How-To: Prevent SPAM with Apache’s mod security
WordPress is a great piece of software to run a blog, it is flexible, has tons of plugins are developed for it and updates are really easy to do. To fight sp...
How-To: Fight SPAM with Postfix RBL
Spam, spam everywhere! If you are hosting your own mail server, fighting spam can become tricky. Antispam solutions do catch a fair amount of them, but still...
How-To: Automatically logout idle bash session
It can be useful to have a bash session automatically closing after some time. One of the obvious reason you might want this to happen is to make sure that n...
How-To: WiFi roaming with wpa-supplicant
wpa_supplicant can be used as a roaming daemon so you can get your system to automatically connect to different network as you are going from one location to...
How-To: Make a file Immutable/Write protected
There might be time when you want to make sure that a file will be protected from accidental/automated change/deletion. While one can protect a file/director...
How-To: tail multiple files with multitail
Many times you will end up tailing multiple files simultaneously. There is a sweet linux utility called multitail that will let you tail multiple files at th...
How-To: Reboot on OOM
Ever had your linux box getting Out of Memory (OOM)? Cleaning up after the OOM killer kicked in to find out that even though OOM killer did a decent job at t...
How-To: find which program consumes your bandwidth with nethogs
Let’s continue the network monitoring serie with yet another use case…. the “What program is using my bandwidth?” problem while not imposible to solve, still...
How-To: monitor network bandwidth usage with vnstat
There is many tools out there that help in monitoring network usage, collect statistics and generate graphs so we can view what happened at a given date/time...
How-To: Bash Parameter Expansion and String Manipulation
Last time we saw how bash can help us in handling default values out of the box using parameter expansion. This time we will see how basic string operations ...
How-To: Bash Parameter Expansion and Default Values
Bash is a sh-compatible command language interpreter that executes commands read from the standard input or from a file. There is much more to bash than run...
Mastering Top
top is most likely one of the most known Linux command and also one of the most used one, however most people do not take full advantage of its capabilities.
How-To: OpenVPN on Debian Squeeze with Username/Password authentication
OpenVPN is a SSL based VPN software that runs on most OS. It is simple to install and run.
How-To: Running Munin 2.0 on Debian Squeeze (6.0)
Munin 2.0 has been released and a .deb package has even been backported to Debian Squeeze!.
How-To: Change boot runlevel with Grub2
Linux start up behaviour is driven by the so-called runlevels. It will use the default value provided in /etc/inittab for some systems (Debian…), or /etc/ini...
How-To: Tmux a Terminal Multiplexer
As a sysadmin, most of my time is spent working on remote machines and different task. tmux is a terminal multiplexer, meaning it allows you to run multiple ...
How-To: Log HAProxy messages only once
When enabling logs with HAProxy on a busy web site, hard disk space can quickly become a scarce resource.
How-To: Set up a L2TP over IPSec VPN using a Radius backend — page 3
In the previous part, we have configured XL2TP
How-To: Set up a L2TP over IPSec VPN using a Radius backend — page 2
We have now configured IPSec, let’s carry on with the next step.
How-To: Set up a L2TP over IPSec VPN using a Radius backend
Even though I pretty like OpenVPN, there is still some devices that might not support the TUN/TAP driver needed by OpenVPN.
How-To: Mounting /dev in a chroot environment
When working in a chrooted environment, there is a few special file systems that needs to be mounted so all programs behave properly.
How-To: Changing the default text editor
There is a few software that will use the editor command to find out what text editor to use. Example commands will be dch to add a new .deb changelog entry,...
How-To: Virtual emails accounts with Postfix and Dovecot — page 3
Following Postfix configuration, it is now time to configure Dovecot.
How-To: Virtual emails accounts with Postfix and Dovecot — page 2
We have set up the database in the first part. Now let’s go ahead and configure our email server to use that database.
How-To: Virtual emails accounts with Postfix and Dovecot
This tutorial will explain how to run a mail server with virtual domains and users using a MySQL backend to store email informations.
How-To: Apache2 authentication using MySQL backend — page 2
In the first part, we have set up our database, let now add some user to authenticate.
How-To: Apache2 authentication using MySQL backend
this tutorial will explain how to use a MySQL backend in order to authentication users against your Apache website.
How-To: Redirecting network traffic to a new IP using IPtables
While doing a server migration, it happens that some traffic still go to the old machine because the DNS servers are not yet synced or simply because some pe...
How-To: Setting up BGP on Vyatta — page 3 — Setting BGP
We have set up our network, now let’s get BGP rolling.
How-To: Setting up BGP on Vyatta — page 2 — Network interfaces
Now that we have defined what we will be setting up, let’s build this up.
How-To: Setting up BGP on Vyatta
Vyatta is a Linux based distro that ease the set up of VPN, Routers, antivirus…. It has a really small footprint on your system as it only requires something...
How-To: Bzr over ssh with no bzr server
Bazaar (bzr) is a distributed version control system (VCS) sponsored by Canonical and thus bzr is widely used by the Ubuntu community.
How-To: encrypted partitions over LVM with LUKS — page 3 — install and config
4. Installing the system
How-To: encrypted partitions over LVM with LUKS — page 2 — encrypting the partitions
3. Encrypting the partitions
How-To: encrypted partitions over LVM with LUKS
Even though new distros installers tend to support filesystem encryption out of the box, most of the time, it might be interesting to actually understand how...
How-To: Remote syslog logging on Debian and Ubuntu
syslogd is the Linux system logging utility that take care of filling up your files in /var/log when it is asked to.
How-To: Set up a LAN gateway with DHCP, Dynamic DNS and iptables on Debian Etch — page 4 — IPtables
We now provide IPs to the hosts in our LAN with our newly installed DHCP server. Now we need to pass their network packets around.
How-To: Set up a LAN gateway with DHCP, Dynamic DNS and iptables on Debian Etch — page 3 — DHCP server
Now that we have configured our DNS server, we need to distribute IPs to the machines in our LAN.
How-To: Set up a LAN gateway with DHCP, Dynamic DNS and iptables on Debian Etch — page 2 — DNS server
1. DNS server
How-To: Set up a LAN gateway with DHCP, Dynamic DNS and iptables on Debian Etch
Linux is a perfect platform to act as a router/gateway.
How-To: copy files over the network and preserve file permissions and informations with ssh and rsync
When copying files over the network, the files informations can be modified.
How-To set up a serial console client
In the 2 previous articles, I explained how to set up a serial console on Ubuntu and Debian.
How-To set up a serial console on Debian
This tutorial will go over the steps to go through in order to set up a serial console on Debian Linux.
How-To set up a serial console on Ubuntu
This tutorial will go over the steps to go through in order to set up a serial console on Ubuntu Linux.
How-To: Customizing SSH client
SSH is great. There is so many thing you can do with it other than just a remote secure shell like X forwarding, port forwarding, authenticate using a privat...
How-To: email notification upon available package updates with cron-apt
cron-apt is a tool run by a cron job at regular interval that will check for package updates and optionally do some actions.
How-To: Customize your Ubuntu Live CD — page 2
We have now set up the base live cd, let’s make this live CD our own by customizing it.
How-To: Customize your Ubuntu Live CD
Live CD are great, they let you try out a distribution without installing it. They allow you to run your favorite distribution on any computer and on the top...
How-To: Find files on your computer with find
A standard Linux system has an incredible amount of files installed. Looking for a file location can be a painful task to do though a file browser.
How-to Create a Filesystem within another partition’s file
Filesystems are usually created on a partition. When all your hard drive is already partitioned, creating a new partition can become a pain and creating a ne...
How-To: create a self-signed certificate
This tutorial will explain how to create a self-signed certificate that you will be able to use with apache in order to provide ssl support.
How-To: Connect to a Cisco VPN with vpnc
This tutorial will show how-to connect to a Cisco VPN Concentrator using vpnc.
How-To: Install Ubuntu on LVM partitions
LVM (Logical Volume Manager) is a great piece of software which allow you to deal with Logical Volumes. Using LVM along with ext3 filesystem, you are allowed...
How-To: Managing services with update-rc.d
Linux services can be started, stopped and reloaded with the use of scripts stocked in /etc/init.d/.
How-To: Unattended Ubuntu Deployment over Network — page 5 — Preseed File
5. Preseed: Installation automation:
How-To: Unattended Ubuntu Deployment over Network — page 2 — DHCP server
For the purpose of this tutorial, I decided to choose dnsmasq to act as a DNS/DHCP server. The reason behind this is that dnsmasq is simple to configure and ...
How-To: Unattended Ubuntu Deployment over Network
there is many ways of installing Linux. Nowadays, the most common one is probably by using a CD. Download the CD, stick it in your CDRom drive and let’s roll...
How-To: Monitor your servers with SNMP and Cacti — page 3
3. Adding new devices to cacti
How-To: Monitor your servers with SNMP and Cacti — page 2
Now that we have our snmp server up and running, we are going to install cacti to manage the snmp server in our network.
How-To: Monitor your servers with SNMP and Cacti
SNMP (Simple Network Management Protocol) is a protocol for managing networks. Each managed entity in the network will run an snmp server (snmpd) which is go...
How-To: FTP Virtual Host with ProFTPD and MySQL — page 2
4. Configure ProFTPd
How-To: FTP Virtual Host with ProFTPD and MySQL
Using ProFTPD and its SQL module for MySQL, it is possible to give FTP access to non system users.
How-To create a MySQL database and set privileges to a user
MySQL is a widely spread SQL database management system mainly used on LAMP (Linux/Apache/MySQL/PHP) projects.
Awstats: Error: Couldn’t open server log file … logresolvemerge.pl … access.log …. No such file or directory
After an upgrade from Debian 3.1 (sarge) to Debian 4.0 (etch), awstats stopped automatically updating.
How-To: Recover root password under linux with single user mode
It happens sometime that you can’t remember root password. On Linux, recovering root password can be done by booting Linux under a specific mode: single user...
How-To set up a LDAP server and its clients — page 2
2. Configuring the clients
How-To set up a LDAP server and its clients
LDAP (Lightweight Directory Access Protocol) allows central user, group, domain….. authentication, information storage …
Samba: How to share files for your LAN without user/password
This tutorial will show how to set samba to allow read-only file sharing for your LAN computers as guest (without be prompted for a password).
Secure your SSH server with Public/Private key authentification — page 3
4. Disabling Authentication by password
Secure your SSH server with Public/Private key authentification — page 2
2. Adding the public key to the authorized key
Secure your SSH server with Public/Private key authentification
Open SSH is the most widely used SSH server on Linux. Using SSH, one can connect to a remote host and gain a shell access on it in a secure manner as all tra...
How-to get your removable device mounted under an explicit and persistent name
You might have wondered how comes that your mp3 player is automatically mounted under a nice name like JUKEBOX for instance, while you usb stick simply get a...
AIDE: Advanced Intrusion Detection Environment
AIDE is an Intrusion Detection System (IDS). Which means that AIDE is not a tool to prevent an intrusion but is actually here to report that an intrusion mig...
Iptables: How-to Share your internet connection — page 4
4. Using iptables’script
Iptables: How-to Share your internet connection — page 3
3.3. Defining custom chains
Iptables: How-to Share your internet connection — page 2
3. Iptables Script
Iptables: How-to Share your internet connection
iptables is a command line tool which allow system administrators to configure Linux packet filtering ruleset.
How-To: Monitoring a Server with Munin — page 2
2. Setting up apache
How-To: Monitoring a Server with Munin
Munin is a simple to configure tool that make real nice graph about your server status. It can actually deal with almost any aspect of your server (load aver...
Postfix and Postgrey: A proactive approach to spam filtering — page 2
4. Tweaking up Postgrey
Postfix and Postgrey: A proactive approach to spam filtering
Greylisting is yet another way for preventing your mailbox getting full of spam. A famous spam fighter software is spamassassin which filter emails. Greylist...
Postfix and Spamassassin: How to filter spam — page 2
3. Make Postfix call Spamassassin
Postfix and Spamassassin: How to filter spam
Postfix is a widely used mail transport agent (MTA) used on many popular Unix/Linux systems. Nowadays, networks are overwhelmed by SPAM mail, fortunately, th...
How To Set up a repository cache with apt-cacher — page 2
3. Setting up the Clients and Server sources.list
How To Set up a repository cache with apt-cacher
When running multiple machine with the same distribution, it is interesting to set up a repository cache on your network so that once a package is downloaded...
Spying Apache server activity and performance with mod_status
On Debian based systems such as Ubuntu… Apache comes with mod_status compiled in by default.
Basic Apache Optimizations — page 2
KeepAlive
Basic Apache Optimizations
Apache, the most popular web server, is a stable and reliable software for providing web pages to the world. But sometimes, it happens that Apache will strug...
Secure your Apache2 with mod-security — page 3
4. mod-security filter examples
Secure your Apache2 with mod-security — page 2
3. Adding Filtering Rules
Secure your Apache2 with mod-security
This article will show how-to install, configure and set up apache’s mod-security module on a debian based system. This was done on Ubuntu Dapper and should ...
How-To: Setting up a DNS zone with Bind9 — page 2
3. Setting up Reverse Name Resolution
How-To: Setting up a DNS zone with Bind9
Bind is a well known Unix name server, it is a powerfull piece of software which is used by the majority of nameservers.
How-To: Apache web server basic security measures — page 2
This is part 2 of How-To: Apache web server basic security measure.
How-To: Apache web server basic security measures
While running a HTTP server such as Apache, there is a few step an administrator have to take in order not to get easily hacked. The very basic one is to hid...
How To: Optimize MySQL response time
High loaded website can get slow to respond when a lot of different visitors visit sites querying the same mysql database server, making it slow to respond.
nload, a network traffic analyser
nload is a ncurse based network traffic analyser. Being a ncurse based tools, you do not need to start X in order to use that software which is necessary whe...
How To: Enable apache modules under Debian based system — page 2
2. Adding modules
How To: Enable apache modules under Debian based system
Apache is usually suitable out of the box for most common used. The apache structure under debian based systems is actually really well made as it is really ...
How To: DPKG guide
This tutorial will bring you through dpkg, the debian package manager. As I introduce apt, I will now introduce dpkg and show how to search which files are i...
How To: subversion SVN with Apache2 and DAV
Subversion is an application used for version control, it is meant to become a replacement of CVS Concurrent Versions System. Subversion is also known as svn.
How To: Exim4 Virtual Host on Debian Etch
Well, since I reinstalled a Debian, I decided to make an article on Exim4, as a complement to Postfix and Virtual Host.
How To: Installing Debian Etch From a running Debian based system — page 3
##5. Install and Configure Xorg
How To: Installing Debian Etch From a running Debian based system — page 2
3. Installing utils package and Configuring your new system
How To: Installing Debian Etch From a running Debian based system
This How To will show how you can install Debian Etch and basically any Debian based distribution from a chroot environment. This way you don’t need to downl...
How To: APT guide
Apt is the debian tool to install, remove and search packages. It is a front-end to the dpkg package manager and offer easy searching, installing …, by using...
Debian-Ubuntu weakness to filesystem corruption recovery
I really love Debian based distribution, namely, Debian itself and Ubuntu, but there is something wrong… The weakest part is located in /var/lib/dpkg/.
How-To: Postfix and Virtual Hosts
Postfix comes as the default mail server under ubuntu. By default, it is set such as it can basically send system notice mail to the user you predefined duri...
Mounting a fuse Filesystem from /etc/fstab
Earlier on, I showed how-to mount a remote filesystem with fuse, using a remote partition accessible by SSH. Since version version 2.4.0, it is possible to u...
How To: Setting up awstats with apache 2 on debian-ubuntu — page 2
3. Configuring Awstats
How To: Setting up awstats with apache 2 on debian-ubuntu
Awstats is a great web log analyser. It gives really useful statistics about traffic on your web sites.
wget, wput or how to easily download-upload over internet
Most unix administrator might know wget, a HTTP, HTTPS and FTP client developped by the GNU project. Using that tool, you can easily download HTTP page but a...
How to: Dapper and Starting MLDonkey: mlnet file[s] not owned by user 113 or group 1001: /var/run — reown it first
Today, when I wanted to start my mldonkey-server from command line, the service reported
How To: Mount a remote filesystem using SSH, SSHFS and FUSE
SSH is a protocol to securely connect to a remote host. In previous article we have seen how-to connect to a remote database through a secured tunnel.
How To: Connect to a remote mysql server using mysqlcc and ssh tunneling part 2
In a previous article we saw how to connect to a remote mysql server running both ssh and mysql.
How-To IPW2200: Getting Intel Pro Wireless 2200 BG to work on debian/ubuntu
A lot of laptop computers using Centrino processor use the Intel Pro Wireless 2200 BG wireless interface, also known as ipw2200.
Using Multiple network device to connect to the internet
It happens sometimes that you get more than one connection to the internet. Also it might not be usefull in most of the cases, there are few cases when it ge...
Virtual Hosting using Apache 2 on a linux machine
Virtual Hosting allow web servers to host more than one website on a sing machine. This is how sharing hosting works. I become pretty handy as well while dev...
How To Connect to a remote mysql server using mysqlcc and ssh tunneling.
This will explain how to connect to a remote mysql server only allowing connections from locahost, from your computer in a secure way as it is being done thr...