Anyone coming from the “sendmail world” to postfix will notice immediately the care taken by postfix developers to make the transition as easy as possible. The same commands you would be used to, like for ex. mailq, newaliases, are working in postfix also.

The newaliases command works on postfix as expected, rebuilding the aliases database:
newaliases

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In a previous article I have shown how you can install memcached from sources, and also how you can install it from debian packages. If you are running RHEL or Centos you have one other choice besides installing memcached from sources. This article will show how you can easily install memcached 1.2.2 and libevent 1.3b using DAG/rpmforge repository. Read the rest of this entry »

This article will explain how you can install the latest memcached daemon (including the libevent library) on a linux system. The only prerequisite for memcached is libevent so we will have to install this first.

Note: the output of the commands in this article are taken from a Debian Etch system. They should work on any recent linux distribution, but depending from your version you might need to make some changes. The versions of memcached and libevent used in this article are the latest stable one existing at the time this was written. Check the download pages bellow, and if newer versions exists you will probably want to use them. Read the rest of this entry »

Almost one month after RedHat released Red Hat Enterprise Linux 5.1 (20071107), the CentOS team released yesterday their own 5.1 update for centos5. There are available new iso images for centos5.1 and we can also find a special netinstall iso that can be used to start a remote install. Systems running centos5 will notice the update in the yum/up2date repositories and can be upgraded immediately.

Besides the changes introduced by rhel5.1 you can find the centos particularities here. Personally I have found it quite strange that after the upgrade the /etc/redhat-release file was not showing 5.1 but still CentOS release 5 (Final), even if centos-release-5-1.0.el5.centos.1.i386.rpm was upgraded:
cat /etc/redhat-release
CentOS release 5 (Final)
instead of something like “CentOS release 5.1 (Final)“. Apparently this is a known issue and the centos team will create wiki page explaining the situation about that in the next couple of days.

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Applies: apache 1.3.x / apache 2.0.x
Required apache module: -
Scope: global server configuration
Type: security

Description: How to disable the HTTP TRACE method on recent apache versions.

Most vulnerability scanners (like the popular nessus, but commercial ones also) will complain (normally as a low thread or warning level) about TRACE method being enabled on the web server tested.

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ldirectord is a daemon to monitor and administer real servers in a LVS cluster of load balanced virtual servers. ldirectord is typically used as a resource for heartbeat , but can also run standalone from the command line.

ldirectord monitors the health of the real servers by periodically running a service check (by default it will know how to check ftp|smtp|http|pop|pops|nntp|imap|imaps|ldap|https|dns|mysql|pgsql|sip) and if a real server fails to respond for the check, then the server is removed from service and will be reactivated once it comes back on line.

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This post is a follow up to the very useful articles posted by Cornelius on Yum usage. As you most certainly know by now, I am a debian/apt fan, but even so I had to work on several centos/fedora/rhel systems many times. One of the nicest features of yum I have found, is the ability to work with software groups. This has been very useful for me in several occasions where I had to clean up a wrong installation (removing a bunch of X related applications on a dedicated server for ex.). Removing several packages by hand would have been very time consuming, but so with just one command all the group (let’s say “X Window System”) can be removed, and with the dependencies also. Very cool!

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I am using on several projects memcached and on the application side the php memcached module. This can be installed as any pear/pecl module, or from source by downloading the source .tgz and running the classic phpize; ./configure; make; make install; While trying to upgrade the memcached module to the latest version available 2.1.2 I encoutered a problem, receiving an error during the compile step:
“configure: error: Cannot find php_session.h”

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This is a well known issue, and it puzzles me that so many peoples don’t know about it. Still whenever I hear of peoples having random crashes with their systems, and they are running RHEL3, the first thing to check is if auditd is still enabled. Disabling auditd is the first things that I would recommend doing, and only after that if the problem still persists to look further into it. After recently doing this on several servers (you would think that most peoples took care of this by now, but it is not so…), I decided to post this in a separate blog entry so I can refer it, as a small step by step instructions anyone can do.
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After my 2nd article on Yum, you should be well prepared for using 3rd party repositories, so here is the list I currently use myself for CentOS 4:

1.) Dag’s repository is my favorite on this list. It contains well tested and stable software for CentOS 4. Famous examples are up-to-date versions of the mailreader pine, spamassassin and many perl modules.

2.) Dries repository is also very useful for some multimedia stuff like mplayer. It also contains some alternatives to the Apache webserver like thttpd and lighthttpd which some of you might find useful.
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