PUBLIC MARKS from alamat with tags linux & tips

The Linux kernel, since version 2.0, has included the capabilities to act as a firewall. In those days, the kernel module was called ipfwadm and was very simple. With the 2.2 kernel, the firewall module became called ipchains and had greater capabilities than its predecessor. Today, we have IPTables, the firewall module in the kernel since the 2.4 days. IPTables was built to take over ipchains, and includes improvements that now allow it to compete against some of the best commercial products available in the market. This guide will give you some background on IPTables and how to use it to secure your network.

I spend most of my time working in front of a black and white terminal of remote SSH connections to various servers. This means that I use bash (as my preferred shell) most of the day. And bash history is a very important feature of bash that saves me much time by recalling previous commands I have typed. Here are some tricks on how you can optimize with some simple configurations settings the usage your bash history.

Bash, which is the default shell in Linux contains a whole lot of key bindings which makes it really easy to use . The most commonly used shortcuts are listed below :

Some of you may be familiar with ftp (File Transfer Protocol). It is not a good idea to use ftp over the Internet because it is a relatively insecure method of transfering files between computers. As most of you know, this protocol sends the user's password and data in the clear over the network, which leaves the user information and data susceptible to password sniffing and other network traffic interception. To transfer files between machines, you need to use scp. scp works very similarly to cp, except that the files you are copying reside on different machines.

SGI loves to try and simplify your life with chkconfig switches to toggle various services on and off. After each upgrade, DOUBLE check the chkconfig switches. If something doesn't work all of the sudden check here.

There is nothing more frustrating for an Administrator who has to reboot system due to fork bomb

In some directories such as /etc you have a mix of file types.

To kill all processes of a particular user from root at unix prompt type:

The creation of many temporary files in Unix during compilations, occupies a lot of memory space. This can be got rid of by using a simple script.

These are some unix tips that might be helpful someday down the road. Feel free to contribute more unix tips by commenting on this article.

Sometimes, I need to connect remote Unix servers with tunnels to provide some specific services or to get access to some internal networks. I was very surprised, when my friend, young system administrator, asked me about how to bring up IP-IP tunnel between different Unix operating systems (FreeBSD and Linux in his case) and said, that he can’t find information about this configuration. As the result of my discovering, this HOWTO has been created.

Either with ckrootkit or with rkhunter.

If you have a couple of old Linux boxes sitting around, then you've got the makings of a supercomputer. Dust them off, install Secure Shell (SSH) and Parallel Virtual Machine (PVM), and start your complex algorithms.

Many people responded to the call for OpenBSD and OpenSSH donations by purchasing an OpenBSD CD set. Those CDs are beginning to arrive in the mail, and when they do, how are you going to use them? If you're a software enthusiast who has never used OpenBSD before, you might enjoy installing it by yourself and figuring it out as you go. If, however, you're looking for a more practical approach to using OpenBSD as a desktop or server operating system, here's a guide to get you started.

Torsmo differs from other system monitors, such as GKrellM, in that it does not spawn a new window, but instead renders text directly to your desktop. It can display almost anything about your system, including uptime, current CPU usage, network activity, hard drive usage, memory usage, and swap usage. The program's developers wrote it to use as little of your system's resources as possible, and it does a good job of this.

Why tune my system? This is probably the first thing you want to know. When a distribution is packaged and delivered to clients, it is designed to be fully compatible with most of the computers available in the market.