SMTP is an abbreviation for “Simple Mail Transfer Protocol”, and is the standard internet protocol for sending email from one system to another. Although the word “simple” belies the inherent complexity of the protocol, SMTP has proved to be a remarkably robust, useful, and successful standard. The design decisions that made it so useful, though, have given spammers and infectious code an easy way to spread their unwanted messages. Its recent evolution reflects the tug-of-war between those unsavory players and the administrators who want to protect their systems and their users.
If you are responsible for maintaining an internet-connected mail-server, then you have, no doubt, come to hate spam and the waste of resources which comes with it. When I first decided to lock down my own mail-server, I found many resources that helped in dealing with these unwanted messages. Each of them contained a trick or two, however very few of them were presented in the context of running a real server, and none of them demonstrated an entire filtering framework.
Dspam filters spam with the best. In my installation, it stops over 98% of all spam: I’ve only had one false positive in the last year, and that was a message to the Dspam list that contained a real spam!
Administering Dspam is a breeze. No rules to configure, new users can automatically benefit from a global dictionary and quarantine management is simple. But getting a Dspam quarantine set up the first time, without losing any email, can challenge the most seasoned mail administrators.
This article weighs the pros and cons of XML for some applications (publishing), and explores why it is the best possible solution for many programming and publishing needs.
In a few years viewing source code within the major components of software infrastructure will probably be a routine way of doing business. In the meantime it seems that the only reason managers want free software is because it is free (as in free of costs). That’s not a good reason in itself: in the long run there are compelling reasons that robust, mission critical infrastructure software should be made free software.
Joomla 1.7 stable release was available on the 19th July 2011. The new features are primarily behind the scenes, and are not as “visible” as features have been for other Joomla upgrades. Yet the new features are very powerful and they include one click upgrades, and Joomla Platform is now split from the cms.
We should all be very grateful to David MacKenzie for having the foresight to--metaphorically speaking--stop and sharpen the ax. Otherwise we'd still be writing (copying) and maintaining long, complex hand-coded
configure scripts today.
In Chapter 1, I gave a brief overview of the Autotools and some of the resources that are currently available to help reduce the learning curve. In this chapter, we're going to step back a little and examine project organization techniques that are applicable to all projects, not just those whose build system is managed by the Autotools.
By default, Drupal allows you to set a "primary" menu and a "secondary" menu. At this point you should know that if you go to admin-> menus -> settings and pick the same menu for both primary and secondary links, the secondary links menu will contain the sub-menu of the selected item in the primary menu.
What happens if you have three levels of menus?
Have you ever tried to figure out how to make Squid authenticate users according to your own exotic rules? Users are in a DB? Are you using an ActiveDirectory? Users/passwords are authenticated by a java class? Everything is possible. Here I intend to explain how to make your own custom authentication helpers so you can develop your own routines for your own requirements.
When you are looking for a workstation or new desktop there are a seemingly infinite number of potential solutions available. So where do you start? Well if you are after a powerful AMD based computer then you might want to take a look at the Sun Ultra 20 M2, a workstation based around AMD Opteron 1200 dual-core CPU, and available at a surprisingly reasonable price.
Workstation or desktop?
Backing up is one of those tedious jobs that has to be done but is usually relegated to the end of the To Do list. Enter Backup Manager, which is a set of Bash and Perl scripts that alleviate the tediousness of performing backups. Taking away some of the complexity of backup tools and combining others, Backup Manager is similar to other backup programs like my pc backup in that it brings simplicity to backing up. Obtaining a higher level view of backups also allows easier management of archives including retention. What follows is a method of backing up a single workstation daily and managing those backups.
So you need a server? Not a web server of course, you rent someone else’s for that. No, you need a file server, print server, intranet, mail server and more. Can free software provide the answer? Of course it can.
Well what kind of answer did you expect from Free Software Magazine?
When my DVD player stopped working, I definitively proved to myself (and to people I know) that if there is a simple and effective solution to a problem and a complex one which promises unpredictable results, I always choose the second option. Instead of buying a new DVD/DivX/MP3 player for the modest price of $40-50, I decided to build a home-made device that would allow me to record the TV, receive podcasts, watch my favorite movies, view webtv, play games, and a lot of other things that I considered cool. So my modest adventure with Freevo, GNU/Linux and a lot other free software begins...
Asterisk is a phone system in software. It can replace large and expensive business phone systems, powering thousands of extensions, or it can help home users save money on long distance. Because it’s implemented in software, it is extremely versatile, easy to customize, and easy to extend.
The need for Asterisk
Part one of this article looked at how Cascading Style Sheets (CSS) can be used to make XML documents look good in a web browser. In part two, I’ll explore the more complex eXtensible Style sheet Language (XSL) and how it can be used to transform XML into HTML and PDF documents.
Limitations of XML/CSS
Creating custom markup with XML is pretty easy to do, but making it look good is another feat entirely. Fortunately, a little knowledge of cascading style sheets can go a long way toward making XML easier on the eyes.
This article looks at the management of the private key for the Software Publishing Certificate (SPC). SPCs are used to digitally sign binaries that are produced by software development vendors. Digitally signing executables proves the identity of the software vendor and guarantees that the code has not been altered or corrupted since it was created and signed. Signing the code requires access to the SPC and the Private Key (PVK) associated with the SPC.
In this article I will describe an experience I had that began with the failure of some RAID5 disks at the Hospital of Pediatric Especialties, where I work. While I wouldn’t wish such an event on my worst enemy, it was something that made me learn about the power of knowledge—a deep knowledge, which is so important in the hacking culture.