blog.up-link.ro
17Jun/100

FreeBSD: System Monitoring with MRTG

The Multi Router Traffic Grapher, or just simply MRTG, is free software for monitoring and measuring the traffic load on network links. It allows the user to see traffic load on a network over time in graphical form.

1. Installing Apache2 HTTP Server

Install Apache on the server you wish to display MRTG stats from:

cd /usr/ports/www/apache22
make install clean

To run Apache2 at system startup, append the following line to /etc/rc.conf :

apache22_enable="YES"

Start Apache2, enter:

/usr/local/etc/rc.d/apache22 start
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12Jun/100

OpenBSD: How To Create a Transparent Bridge

A network bridge is a device which connects two parts of a network together. In this article I'll show you how to create a transparent bridge in OpenBSD.

To activate the bridge in OpenBSD run the following commands:

echo up > /etc/hostname.xl0
echo up > /etc/hostname.xl1
echo add xl0 add xl1 up > /etc/bridgename.bridge0

This will setup the two interfaces (xl0 and xl1) and add them into the bridge0.

Now, you need to enable IP forwarding so that IP packets will pass from one interface to another.
To enable ip forwarding add the following line to /etc/sysctl.conf:

 net.inet.ip.forwarding=1

Once this is all done, reboot to activate.

reboot

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11Jun/100

OpenBSD: How To Install OpenBSD Ports and Packages Collection

OpenBSD is a fairly complete system of its own, but still there is a lot of software that one might want to see added.

The port collection, originally borrowed from FreeBSD and significantly rewritten, fills this gap. The concept is to have, for each third-party software, a Makefile that controls:

  • where to fetch it,
  • how to do the fetch,
  • what it depends upon (if anything),
  • how to alter the sources (if needed),
  • how to configure, build and install it.

This information is kept in a directory hierarchy under the /usr/ports directory.

Packages are the binary equivalent of ports. A compiled port becomes a package that can be easily installed and registered into the system using pkg_add utility.

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10Jun/100

OpenBSD: How To Install OpenBSD – OpenBSD 4.7 Installation Guide

OpenBSD is a Unix-like operating system descended from Berkeley Software Distribution (BSD), a Unix derivative developed at the University of California, Berkeley.

The OpenBSD project produces a FREE, multi-platform 4.4BSD-based UNIX-like operating system. OpenBSD supports binary emulation of most programs from SVR4 (Solaris), FreeBSD, Linux, BSD/OS, SunOS and HP-UX.

This article is a step-by-step guide about how to install OpenBSD 4.7 using the installation CD. The installation guide will show a clean install, meaning any operating system or information already on the computer will be erased.

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26May/100

How To Install and Configure ddclient in FreeBSD and Linux to work with OpenDNS

ddclient is an open-source dynamic IP update client written in Perl. ddclient is available here.

This article shows how to install and configure ddclient in FreeBSD and Linux so it will update your OpenDNS account with your dynamic IP from your ISP.

1. Installation

For CentOS / Fedora, install ddclient via yum:

yum install ddclient

For Debian and Ubuntu, install ddclient via apt-get:

apt-get install ddclient

For FreeBSD, install ddclient from the FreeBSD ports collection:

cd /usr/ports/dns/ddclient
make install clean

2. Configuration

After installing ddclient, you have to create / edit ddclient.conf ( for FreeBSD the configuration should be located in /usr/local/etc, for CentOS should be located in /etc/ddclient and for Debian or Ubuntu in /etc ) as follows:

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22May/100

How To Install OpenVPN in FreeBSD

OpenVPN is a an open source software application that implements virtual private network (VPN) solutions for creating secure point-to-point or site-to-site connections in routed or bridged configurations and remote access facilities. OpenVPN uses SSL/TLS security for encryption and is capable of traversing network address translators and firewalls.

I. OpenVPN Server - Installation and Configuration

1. Installing OpenVPN Server

To install OpenVPN from FreeBSD ports, enter:

cd /usr/ports/security/openvpn
make install clean

OpenVPN Installation Screenshot 1

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21May/100

How To Update CentOS Linux 5.4 to CentOS 5.5

CentOS ( Community ENTerprise Operating System ) is a community-supported, mainly free software operating system based on Red Hat Enterprise Linux. It exists to provide a free enterprise class computing platform and strives to maintain 100% binary compatibility with its upstream distribution.

CentOS 5.5 has been released and available via mirrors for immediate update. For more information about this release you can read the release note.

If you have CentOS 5.4 already installed, before to do anything first back up anything you care about.

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17May/100

How To Install Lighttpd with PHP5 and MySQL support on CentOS 5

Lighttpd is an open-source web server optimized for speed-critical environments. It's standards-compliant, secure and flexible. In this tutorial I'll show you how to install Lighttpd on a CentOS 5.4 server with PHP5 support (through FastCGI) and MySQL support.

1. Installing MySQL 5 Server

To install MySQL run this command from the shell:

# yum install mysql mysql-server

Enable MySQL server on boot and start MySQL server:

# chkconfig --levels 235 mysqld on
# service mysqld start

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7May/100

Linux Security: Access Rights and Permissions for Files and Directories

1. Introduction

The Linux security model is based on the one used on UNIX operating systems. On a Linux system, every file is owned by a user and a group user. There is also a third category of users, those that are not the user owner and don't belong to the group owning the file.  For each category of users, read, write and execute permissions can be granted or denied.

The file permissions for these three user categories are indicated by the nine characters that follow the first character, which is the file type indicator at the beginning of the file properties line. The first three characters in this series of nine display access rights for the actual user that owns the file. The next three are for the group owner of the file, the last three for other users.

The permissions are always in the same order: read, write, execute for the user, the group and the others.

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1May/100

How To Limit CPU Usage of A Process with cpulimit under Linux

In this tutorial I'll show you how you can limit the CPU usage of a process with cpulimit tool on Debian/Ubuntu Linux.
cpulimit is a program that limit the CPU Usage of a process (expressed in percentage, not in CPU Time). This is very useful to control batch jobs, when you don't want them to use to much CPU. cpulimit is able to adapt itself to the overall system load, dynamically and quickly.

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