PUBLIC MARKS with tags tutorial & serveur

Cet article est le premier d’une série sur l’admin système linux. On va donc commencer par les bases : installer un ubuntu server avec une sécurité correcte et on en profite pour installer un LLMP dessus (c’est LAMP mais avec Lighttpd à la place de apache :-) )

Nagios is a powerful, modular network monitoring system that can be used to monitor many network services like smtp, http and dns on remote hosts. It also has support for snmp to allow you to check things like processor loads on routers and servers. I couldn't begin to cover all of the things that nagios can do in this article, so I'll just cover the basics to get you up and running.

Cela fait près d’un an et demi que j’utilise le logiciel Cacti pour monitorer l’activité réseau. Aussi bien dans le cadre de mon activité professionnelle que pour mon usage personnel. Mais j’ai récement découvert une alternative sérieuse : Munin. Celui-ci présente de nombreux avantages par rapport à Cacti et mérite d’être plus connue.

A while back I stumbled upon a lesser known feature of SVN and WebDav, but didn’t have the time to blog about it until now. WebDAV and SVN is an exceedingly useful tool as we all know, and pretty damn easy to setup, see here. But what if you could have everything entered into the WebDav repository automatically versioned into a repository. Well you can! And the good news is, it’s really really easy.

This article shows how to integrate amavisd-new into a Postfix mail server for spam- and virus-scanning. amavisd-new is a high-performance interface between MTAs such as Postfix and content checkers: virus scanners, and/or SpamAssassin. We will use ClamAV for virus scanning and SpamAssassin for spam scanning in this tutorial. 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!

This document requires Postfix version 2.0 or later. This document gives an overview of how Postfix can be used for hosting multiple Internet domains, both for final delivery on the machine itself and for the purpose of forwarding to destinations elsewhere. The text not only describes delivery mechanisms that are built into Postfix, but also gives pointers for using non-Postfix mail delivery software.

Not everyone knows about PHP's capabilities of making SSH connections and executing remote commands, but it can be very useful. I've been using it a lot in PHP CLI applications that I run from cronjobs, but initially it was a pain to get it to work. The PHP manual on Secure Shell2 Functions is not very practice or thorough for that matter, so I would like to share my knowledge in this how to, to make it a little less time consuming setting this up. In this article I'm going to assume that: * You're running Debian / Ubuntu If not, you will have to substitute the package manager aptitude with whatever your distribution provides * You're running PHP 5 If not, just replace php5 with php4 everywhere * You have basic knowledge of PHP & server administration * You already have PHP installed

C’est simple copie est assez simple à mettre en place, et peut s’avérer très pratique en cas de crash du disque dur. La sauvegarde peut paraitre un peut basique, mais qui à besoin (et qui à assez d’espace disque) pour avoir une sauvegarde jours par jours avec les modifications ?

Our intention is not to build a fail-safe system nor a HA-Linux. We are just using RAID-1 mirrored disks to make sure that the system can be restored easily if 1 disk crashes. The following has been tested only twice (hey, we've got other things to do). It did work for us, it might work for you. It might also make your rats go berserk or just blow your mind.

SSH also has a wonderful feature called SSH Port Forwarding, sometimes called SSH Tunneling, which allows you to establish a secure SSH session and then tunnel arbitrary TCP connections through it. Tunnels can be created at any time, with almost no effort and no programming, which makes them very appealing. In this article we look at SSH Port Forwarding in detail, as it is a very useful but often misunderstood technology. SSH Port Forwarding can be used for secure communications in a myriad of different ways. Let's start with an example.

Security is best when it is handy. ssh-agent is pretty darn handy. Ssh-agent can authenticate you to a remote machine via keypairs, rather than the traditional hand-typed username/password combination, with no loss of security.

Security is best when it is handy. ssh-agent is pretty darn handy. Ssh-agent can authenticate you to a remote machine via keypairs, rather than the traditional hand-typed username/password combination, with no loss of security.

A RAID device is a Redundant Array of Independent Disks. The concept was developed in 1987 at UC Berkeley and involves the creation of a virtual disk from multiple small disks in order to deliver improved performance and reliability. There are many flavors of RAID and lots of variations in how to implement it. We detail here a specific instance we use: software RAID1 using IDE disks on a Dell PowerEdge box running Debian "sarge" loaded with grub, managed by mdadm, using the ext3 journaling file system.

The system is equipped with 2 similar hard disks (they do not have to be the same but it helps if they are at least similar). The first disk is attached to the primary IDE as master, it will be referenced as /dev/hda. The second disk is attached to the secondary IDE also as master, it will be referenced as /dev/hdc.

wondershaper is an easy to use traffic shaping script that provides these improvements: * Low latency for interactive traffic (and pings) at all times * Allow websurfing at reasonable speeds while uploading / downloading * Make sure uploads don't hurt downloads * Make sure downloads don't hurt uploads

The purpose of this document is to describe how to install OpenVPN server on an Ubuntu Linux system and have it utilize an Ethernet bridge to access your local network. Ethernet bridges essentially allow the operating system to treat multiple network interfaces as one combined port. When used with OpenVPN a bridge will allow you to easily connect external users to your internal network and have them receive all traffic as though they were locally connected. The alternative is to use OpenVPN with a route but that will not allow some forms of traffic through (such as multicast), multicast traffic is important to me as many games require multicast data.

Ce document explique comment mettre en place plusieurs types différents de RAID logiciel sur une plateforme Linux.

The process for converting a VMWare VMDK disk image to Xen HVM is rather quite easy. However, there are "gotchas" that you need to consider when doing this conversion.

Howto run smoothwall on Xen.

Smoothwall Express is an internet firewall, which allows you to protect your network, as well as providing NAT functionality. It is ease to use and configurable via a web-based GUI. This open source firewall distribution requires absolutely no knowledge of Linux to install or use. This workshop shows the installation and basic configuration of the current release Smoothwall Express 3.0.

There is a great howto about installing Xen on Debian Unstable. It is really easy to do and it runs fine. Nevertheless, on production servers, that's not an optimal solution. Debian Unstable has too many updates and things change too often. On production machines, a Xen host system should be stable, secure and should not need much attention. That is where Sarge comes in. If you pull the Xen packages from backports and install them on Debian stable you've got the best of both worlds. Let's do so!

Ce document a pour but d'expliquer les rudiments de la sécurité d'une machine Linux placée dans un réseau local (typiquement une maison on un appartement), reliée à Internet. Il est tout particulièrement destiné aux utilisateurs néophytes, ou n'ayant pas ou peu de connaissance sur la sécurité informatique en général, et sous Linux en particulier.

Lastly on one of the domU's, I had recently upgraded it to Etch. It was rebooted previously and did work. However after going back to Xen with Backports, its network didnt work.