PUBLIC MARKS from camel with tags debian & linux

This tutorial explains how you can set up MySQL master-master replication on four MySQL nodes (running on Debian Etch). The difference to a two node master-master replication (which is explained here) is that if you have more than two nodes, the replication goes in a circle, i.e., with four nodes, the replication goes from node1 to node2, from node2 to node3, from node3 to node4, and from node4 to node1. Since version 5, MySQL comes with built-in support for master-master replication, solving the problem that can happen with self-generated keys. In former MySQL versions, the problem with master-master replication was that conflicts arose immediately if node A and node B both inserted an auto-incrementing key on the same table. The advantages of master-master replication over the traditional master-slave replication are that you don't have to modify your applications to make write accesses only to the master, and that it is easier to provide high-availability because if the master fails, you still have the other master.

GreenSQL (or greensql-fw) is a firewall for MySQL databases that filters SQL injection attacks. It works as a reverse proxy, i.e., it takes the SQL queries, checks them, passes them on to the MySQL database and delivers back the result from the MySQL database. It comes with a web interface (called greensql-console) so that you can manage GreenSQL through a web browser. This guide shows how you can install GreenSQL and its web interface on a Debian Etch server.

This article explains how you can install and configure apache2-mpm-peruser on a Debian Etch server. apache2-mpm-peruser is an MPM (Multi-Processing Module) for the Apache 2 web server, very similar to apache2-mpm-itk, but faster (almost as fast as apache2-mpm-prefork). mpm-peruser allows you to run each of your vhosts under a separate UID and GID - in short, the scripts and configuration files for one vhost no longer have to be readable for all the other vhosts. It is based on metuxmpm, a working implementation of the perchild MPM. The result is a sane and secure web server environment for your users, without kludges like PHP's safe_mode.

This article shows how to install and configure ModSecurity (version 2) for use with Apache2 on a Debian Etch system. ModSecurity is an Apache module that provides intrusion detection and prevention for web applications. It aims at shielding web applications from known and unknown attacks, such as SQL injection attacks, cross-site scripting, path traversal attacks, etc. I want to say first that this is not the only way of setting up such a system. There are many ways of achieving this goal but this is the way I take. I do not issue any guarantee that this will work for you!

mod_defensible is an Apache 2.x module intended to block spammers/hackers/script kiddies using DNSBL servers. It will look at the client IP and check it in one or several DNSBL servers and return a 403 Forbidden page to the client. This guide shows how to install and use it with Apache 2 on a Debian Etch server.

This tutorial is based on Falko Timme's tutorial for MySQL Cluster 5.0. It shows how to configure a MySQL 5.1 cluster with five nodes: 1 x management, 2 x storage nodes and 2 x balancer nodes. This cluster is load-balanced by an Ultra Monkey package which provides heartbeat (for checking if the other node is still alive) and ldirectord (to split up the requests to the nodes of the MySQL cluster). In this document I use Debian Etch 4.0 for all nodes. Therefore the setup might differ a bit for other distributions. The two data nodes were x64 to use all of the 8GB RAM. Servers were compiled from source so you should be able to make it running on any platform. The MySQL version I use in this setup is 5.1.24-rc. It's a release candidate, but I wanted to use 5.1 to take advantage of Memory-Disk Based tables. Beginning with MySQL 5.1.6, it is possible to store the non-indexed columns of NDB tables on disk, rather than in RAM as with previous versions of MySQL Cluster.

First and foremost, be prepared to have some patience when trying to get a USB cam to work under Linux. In trying to get mine to work, I searched many a newsgroup thread only to find there was only one message in the thread, the original question stating the problem. i.e. no one had an answer for the person who posted the question so you may be on your own trying to get your cam to work. Often times the same camera model will use different drivers for different sub-models (ex: not all QuickCam Express sub-models use the same driver). However, my trials and tribulations were a good learning experience and I'll share what I learned here to hopefully make your setup easier.

sortie de la version 4.3 de Damn Small Linux. C’est une distribution très légère de 50Mo environ basée sur Knoppix, Debian et GNU Linux. Elle peut s’intaller sur : * Une clé USB, * Une carte Compact Flash via la méthode dite “Frugal Install”, * Un mini-cd, * Un ordinateur 486DX avec 16MB de RAM, * 128 Mo de mémoire RAM. Bref, une pure merveille pour les vieilles machines ou les petites configuration (les pc embarqués et les nano-ITX). A l’intérieur, des tonnes de logiciels. Et oui, avec 50 Mo vous pourrez en faire des choses.Navigateur, client Mail, suite office légére, XMMS, client FTP, AIM, ICQ, …

Imagine you have a machine with all of its disk full and another with unused gigabytes, and you don't want to move the data from one to the other. Why not using the second's disk on the first, you can do it with iSCSI but you can do it with ATA over Ethernet (AoE) too. It's the second method I'll explain in this article. All of this was made with two computers running Debian Etch.

This guide explains how to set up mod_geoip with Apache2 on a Debian Etch system. mod_geoip looks up the IP address of the client end user. This allows you to redirect or block users based on their country. You can also use this technology for your OpenX (formerly known as OpenAds or phpAdsNew) ad server to allow geo targeting.

djbdns is a very secure suite of DNS tools that consists out of multiple parts: dnscache, a DNS cache that can be used in /etc/resolv.conf instead of your ISP's name servers and that tries to sort out wrong (malicious) DNS answers; axfrdns, a service that runs on the master DNS server and to which the slaves connect for zone transfers; and tinydns, the actual DNS server, a very secure replacement for BIND.

This article explains how to set up a two-node load balancer in an active/passive configuration with HAProxy and heartbeat on Debian Etch. The load balancer sits between the user and two (or more) backend Apache web servers that hold the same content. Not only does the load balancer distribute the requests to the two backend Apache servers, it also checks the health of the backend servers. If one of them is down, all requests will automatically be redirected to the remaining backend server. In addition to that, the two load balancer nodes monitor each other using heartbeat, and if the master fails, the slave becomes the master, which means the users will not notice any disruption of the service. HAProxy is session-aware, which means you can use it with any web application that makes use of sessions (such as forums, shopping carts, etc.). From the HAProxy web site: "HAProxy is a free, very fast and reliable solution offering high availability, load balancing, and proxying for TCP and HTTP-based applications. It is particularly suited for web sites crawling under very high loads while needing persistence or Layer7 processing. Supporting tens of thousands of connections is clearly realistic with todays hardware. Its mode of operation makes its integration into existing architectures very easy and riskless, while still offering the possibility not to expose fragile web servers to the Net."

Lighttpd is a secure, fast, standards-compliant web server designed for speed-critical environments. This tutorial shows how you can install Lighttpd on a Debian Etch server with PHP5 support (through FastCGI) and MySQL support.

This is a document about how to set up XEN and iSCSI on 3 Debian Stable (3.1 / Sarge) machines so that you can have a virtual host that can be migrated live between 2 of the machines. The third machine will be the common disk for the virtual machine that is seen via the 2 machines running XEN. I have assumed you have some knowledge of Linux specifically Debian, but not limited to. You may need to solve some dependencies that I have left out by yourself. I can't think of everything, and I didn't start with completely empty machines.

Lighttpd, sometimes pronounced "Lighty", is a lightweight HTTP server that can help alleviate Apache's load by serving static content. Since Lighttpd uses less resources per request than Apache, it generally serves most static content faster than Apache. This tutorial shows how to install Lighttpd behind Apache via Apache´s proxy module.

djbdns is a very secure suite of DNS tools that consists out of multiple parts: dnscache, a DNS cache that can be used in /etc/resolv.conf instead of your ISP's name servers and that tries to sort out wrong (malicious) DNS answers; axfrdns, a service that runs on the master DNS server and to which the slaves connect for zone transfers; and tinydns, the actual DNS server, a very secure replacement for BIND.

Nous verrons dans cet article comment installer Xen sur une machine n'ayant pas les instructions matérielles de virtualisation (VT) en utilisant LVM pour partitionner avec flexibilité nos différentes machines virtuelles. Le tout est réalisé grâce à Debian Etch avec les bons noyaux qui vont bien. J'ai aussi utilisé le noyau officiel de chez Xen afin d'avoir quelque chose de propre (enfin dans la limite du possible). Attention, mon tutoriel prends de véritables adresses IP, je n'ai donc aucun besoin de NAT. Si tel est votre problème, achetez le numéro 100 de GLMF, il contient le serveur parfait et un setup bien plus avancé que le miens :)

This short guide describes how to install Windows XP or Windows 2003 Server on Xen. It provides an overview of the Debian Linux Etch installation, and detailed steps for installing and configuring Xen and starting the Windows XP or Windows 2003 Server installation.

Ganeti is a cluster virtualization management system based on Xen. In this tutorial I will explain how to create one virtual Xen machine (called an instance) on a cluster of two physical nodes, and how to manage and failover this instance between the two physical nodes.

If you have a server with more than 4GB RAM and want to install a 32bit Debian Etch on it (following this tutorial: Debian Etch And Xen From The Debian Repository), you'd expect the Xen-PAE kernel to see all your RAM because the Xen-PAE kernel supports up to 64GB RAM. In fact, it recognizes only about 3.3GB RAM due to a bug in the GRUB bootloader. This article explains how you can fix GRUB so that all your RAM gets recognized. I do not issue any guarantee that this will work for you!