File and mail security is easy to achieve with the right tools. PGP has proven itself the leader, and GnuPG is the tool of choice in the Linux world.

Linux has a powerful task scheduler called Cron. Cron will allow you to run commands automatically at times specified by you. Cron is similar to the task scheduler you find in Windows. To keep track of the schedules and tasks it has to run, Cron requires a file called Crontab (CRON TABle). All the Cron schedules and tasks should be stored in this table. The Crontab files cannot be directly edited. You can add or delete entries in the crontab file using the crontab command.

What are your IT Career and Certification expectations for year 2004? While certifications can give you an edge, going for just any certification doesn’t help. What is your career focus? New or old activities, what is your focus? New does not always translate to good or wise. It makes sense to review and analyze trends that will affect your career in 2004.

The Kerio Mail Server is a cross platform ( Windows, Linux, and Mac OSX) mail server. I tested it on RedHat Linux 8.

I have a very good memory. I remember most of my client’s passwords (there are a few I forget regularly for no reason that I can understand, but I really do know most), I remember telephone numbers, and of course I know my own passwords. That last isn’t as easy as it might sound, because I have quite a few different systems and each has its own password, but though I might use the wrong one now and then, I’ll get it on the second or third try.

Last time we set up a Perl script that would use the Net::Pcap module to sniff the network and print information about DNS requests to standard output. The output looks like this

sourceipaddr -> destipaddr: dnshostname

Most people have heard of Nmap, the ubiquitous portscanner and more, available at http://www.insecure.org/nmap/. Recently, a new version of Nmap was released with a new and frequently requested feature – version scanning.

Most Linux distributions use the RPM[1] format for their software packages. RPMs are managed by the rpm program, which typically lives at /usr/bin/rpm.[2]

This week, we’ll take a look at a successful and somewhat puzzling machine compromise. The machine in question was a production machine that had been up and running for about a year – one of those machines that had so much on it that you’re afraid to ever reboot it, lest something not come back up.

Many modern systems provide a way to watch a directory for events (new files, reading the directory, modification of a file in the directory, etc.). This facility can be done in various ways, from providing hooks in the filesystem code itself to something that watches for inode changes. Linux and BSD have several possibilities in that regard, including dnotify, changedfiles, and watch.

Warning: This article contains strong language and unpopular opinions. Reading of this material by Windows advocates may cause severe gastric distress followed by a desire to strike the author sharply about the head. As the author does not enjoy being pummeled, such persons are kindly requested to return whence they came and do something else.

People consider the GNU or free software and open source software to be unsafe and are supposed to easily compromised because their source code are readily available,which isn’t correct. This article is specifically related for the security of the GNU Linux Operating system and will help the person for enabling the security parameters for added safety.

Problem
You want a service to be available only at certain times of day.

Problem
You want to create an encrypted backup.

These are classic Unix permissions. However, many modern Unixes support extended attributes that go beyond this. We’ll look at one example of that later in the article. You also need to know that Unix and Windows permissions don’t map well to each other, so if you are using something like Samba or Visionfs , you need to understand how permissions will be shown and honored. Some examples of that are shown later.

Virtual PC for Windows, Mac (OS 9 or X) and OS/2 creates virtual machines that can run multiple Windows versions. This is particularly advantageous for Mac users, but even ordinary PC users can find value in this. It’s easy to have Linux, Windows 98, Windows ME, 2000, XP Home and XP professional all on the same machine.

The /proc filesystem is one of Linux’s great features, and this article gives you a thorough grounding in some of its most useful aspects. With it, you can administer many details of the operating system without ever having to shut down and reboot the machine, which is a boon for those who need to keep their systems as available as possible.

Building a reliable, full-featured broadband router can be very easy and cost-efficient. This article is about building one for routing a LAN to the Internet with NAT (Network Address Translation — Linux users also call it as IP Masquerading) using an old computer and a Linux micro-distribution designed to have very low hardware requirements. We’ll end up having a very simple and stable system, yet featuring e.g. iptables based stateful firewalling and remote administration.

If the company Red Hat has its way, its Red Hat Certified Engineer (RHCE) credential will eventually replace Microsoft’s MCSE certification as king of the network operating system hill.

In this article we’ll describe how to connect two PC via SLIP protocol using a null-modem cable. After this procedure, the two PCs will be connected and the IP protocol will be available for interworking, so using IP applications (e.g. telnet, ftp, ping) will be possible.

Almost all modems manufactured today are software modems, usually referred to as “winmodems”. Even though we pay a lot for a winmodem, they are cheap to manufacture because they use very little electronics. The functions that should be performed in hardware are emulated by software. This places an extra processing burden on your computer’s CPU. Winmodems will not work with Linux unless you can locate a special “Linmodem” driver.