Unix News

In this article I will describe how to install munin on 2 computers, but you can add more if you want to, this will allow us to remotely monitor system performance and activity

Infiniband is an interconnect technology that breaks through the bandwidth and fanout limitations of PCI bus by switching from traditional shared bus architecture to a switched fabric architecture. It is a switched fabric I/O technology that ties together servers, storage devices, and network devices. Instead of sending data in parallel, which is what PCI does, Infiniband sends data in serial and can carry multiple channels of data at the same time in a multiplexing signal. more ..

Bad habits are hard to break. But habits that you've just become comfortable with can be even more difficult to overcome. Sometimes, a fresh look at things may provide you with an "A-ha, I didn't know you could do that!" moment. Building on Michael Stutz's excellent article, " Learn 10 good UNIX usage habits ," this article suggests 10 more UNIX command-line commands, tools, and techniques that may make you more productive as a UNIX command-line wizard.

In this chapter , we discuss the ways mod_perl makes it possible to share data between processes or even between different handlers.

An automounter allows the binding of a directory name to a filesystm to be delayed until the name is referenced. This can be advantageous merely to reduce the number of simultaneous mounts, but it can improve system reliability, simplify administration and provide transparent redundancy as well. Examples of automouters are autofs (supplied with Linux) and automountd (supplied with SUNOS) Amd is an advanced automounter, with great flexibility. It is the default automounter pre-installed in FreeBSD and is currently maintained for over 100 operating systems by Erez Zadok. As of the fall of 2000, it is at version 6.04. more ...

The Linux world has many excellent programs for handling email: Sendmail, Exim, qmail, and Postfix are the top four mail transfer agents (MTAs). This chapter covers Postfix. Like most of the post-Sendmail generation of MTAs, Postfix is designed from the ground up to be secureable and robust. It scales nicely from the single user who wants more control over her personal mail all the way up to the largest service provider.

A new security advisory has recently been released relating to the Debian openssl package, and whilst most security updates are not news-worthy this one is. Read on for a brief overview of the problem. more ...

While Linux is more secure against an invasion over the Internet, more is not necessarily enough. A firewall, software that allows you fine-grained control over your connection in and out of your computer, is the next step in increasing security. While Linux has had built-in firewalling software for many years, configuration of that software was a combination of a lot of research and some cryptic commands.

One of the things that makes Linux more secure than some operating systems is a permission system and separate logins. This adds the complication that some administrative tasks must be done using the administrator login (called root) but that is a small price to pay for the added level of security, read more...

Ever wonder what makes a computer tick or how a UNIX® server does what it does? For those who wonder what happens when you push the power button on your computer, here's your inside look. This article discusses the different boot types, managing the IBM® AIX® bootlist, and the AIX boot sequence. After reading this article, you should have a better understanding of what exactly is happening when your server starts.

yacc and lex are tools for generating language parsers. We observed in Chapter 8 that your first minilanguage is all too likely to be an accident rather than a design. That accident is likely to have a hand-coded parser that costs you far too much maintenance and debugging time—especially if you have not realized it is a parser, and have thus failed to properly separate it from the remainder of your application code. more ...

Sun's Solaris will soon appear in a native 64-bit version for the AMD64 architecture. While you can already run the 32-bit version of Solaris x86 today, Alan Zeichick explains the significance of this new operating system release, and highlights Sun's plans to support the AMD Opteron and Athlon 64 processors.

Malicious SSH login attempts have been appearing in some administrators' logs for several years. This article revisits the use of honeypots to analyze malicious SSH login attempts and see what can be learned about this activity. The article then offers recommendations on how to secure one's system against these attacks.

This tutorial covers the creation and useage of boot floppies for system recovery. Three recovery methods are discussed: 1- Creation / useage of a floppy with GRUB boot loader. Grub configured on floppy to point to Linux kernel on hard drive. 2- Creation / useage of a floppy with LILO on the Master Boot Record (MBR) to point to the Linux kernel on an existing hard drive for boot. This is typically done when the MBR is corrupted, overwritten by the installation of another operating system or as an alternative to configuring the hard drive MBR for dual boot, more...

Linux® has been described as one of the most secure operating systems available, but the National Security Agency (NSA) has taken Linux to the next level with the introduction of Security-Enhanced Linux (SELinux). SELinux takes the existing GNU/Linux operating system and extends it with kernel and user-space modifications to make it bullet-proof. If you're running a 2.6 kernel today, you might be surprised to know that you're using SELinux right now! This article explores the ideas behind SELinux and how it's implemented.

You want to determine if insecure protocols are being used on the network. Use dsniff. To monitor the network for insecure protocols: # dsniff -m [-i interface] [-s snap-length] [filter-expression] To save results in a database, instead of printing them: # dsniff -w gotcha.db [other options...] To read and print the results from the database: read more...

Suppose you needed to open a connection to a remote host from within your perl program. One thing you would probably think of doing at first is the following: more ...

Sometimes you might want to restrict users to specific directories so that they are not able to look into the whole system. This can be achieved by creating the chroot users. This article describes how to set up an IBM® AIX® chroot environment and use it with ssh, sftp, and scp. You will also learn about the prerequisites for AIX and openssh, and how to configure and use a chroot environment. A downloadable sample shell script that automatically sets up this environment is also provided.

The Linux-Infrared-HOWTO (former known as IR-HOWTO) deals with Linux and infrared devices. These are usually IrDA(TM) capable devices, but also LIRC (Linux Infrared Remote Control) is covered. Attention: the new 2.6 Kernel series contains substantial changes to the IrDA subsystem, which are not covered in detail in the HOWTO.

Test::More normally expects to be told how many tests are in the 'dot-T' file in question. But as we are actively developing our test cases, we'll use the 'no_plan' directive let it know there is no count available. So on to writing an actual test case. Test::More provides a number of functions to test your modules public interface., the general form of which is method( , , "comment"), more ...

These instructions are currently for open source Xorg 7.2 AIGLX drivers for i810, r200.

This article discusses how to deal with masked packages. For information on why packages are masked and the official methods of dealing with them, please see the Gentoo Handbook: Working With Portage: Mixing Software Branches.

In Part 1 we looked at some of the great hardware choices for building a custom Linux-based wireless access point, including mini-ITX and embedded systems. Here we'll learn how to convert an ordinary old PC into a powerful, customizable access point.

For ultimate control and customizability, building your own Linux wireless access point is the way to go. You may use an old recycled PC, or build a sleek attractive power- and space-saving unit from new parts.