BIND 9 is an implementation of the Domain Name System (DNS) protocols. named daemon is an Internet Domain Name Server for UNIX like operating systems. Dynamic update messages may be used to update records in a master zone on a nameserver. When named receives a specially crafted dynamic update message an internal assertion check is triggered which causes named to exit. An attacker which can send DNS requests to a nameserver can cause it to exit, thus creating a Denial of Service situation. configuring named to ignore dynamic updates is NOT sufficient to protect it from this vulnerability. This exploit is public. Please upgrade immediately. [continue reading…]
OpenSSH is the implementation of the SSH protocol. OpenSSH is recommended for remote login, making backups, remote file transfer via scp or sftp, and much more. SSH is perfect to keep confidentiality and integrity for data exchanged between two networks and systems. However, the main advantage is server authentication, through the use of public key cryptography. From time to time there are rumors about OpenSSH zero day exploit. This page shows how to secure your OpenSSH server running on a Linux or Unix-like system to improve sshd security. [continue reading…]
Linux kernel is the central component of Linux operating systems. It is responsible for managing the system’s resources, the communication between hardware and software and security. Kernel play a critical role in supporting security at higher levels. Unfortunately, stock kernel is not secured out of box. There are some important Linux kernel patches to secure your box. They differ significantly in how they are administered and how they integrate into the system. They also allow for easy control of access between processes and objects, processes and other processes, and objects and other objects. The following pros and cons list is based upon my personal experience. [continue reading…]
Geolocation software is used to get the geographic location of visitor using IP address. You can determine country, organization and guess visitors location. This is useful for
a] Fraud detection
b] Geo marketing and ad serving
c] Target content
d] Spam fighting
e] And much more.
mod_geoip is a Lighttpd module for fast ip/location lookups. In this tutorial you will learn about mod_geoip installation and php server side examples to determine visitors country. [continue reading…]
The tail command is one of the best tool to view log files in a real time using tail -f /path/to/log.file syntax on a Unix-like systems. The program MultiTail lets you view one or multiple files like the original tail program. The difference is that it creates multiple windows on your console (with ncurses). This is one of those dream come true program for UNIX sys admin job. You can browse through several log files at once and do various operations like search for errors and more. [continue reading…]
Some time ago ext4 was released and available for Linux kernel. ext4 provides some additional benefits and perforce over ext3 file system. You can easily convert ext3 to ext4 file system. The next release of Fedora, 11, will default to the ext4 file system unless serious regressions are seen. In this quick tutorial you will learn about converting ext3 to ext4 file system. [continue reading…]
Linux / BSD and UNIX like operating systems includes software from the OpenSSL Project. The OpenSSL is commercial-grade, industry-strength, full-featured Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as general purpose cryptography library.
The Google security team discovered a flaw in the way OpenSSL checked the verification of certificates. An attacker in control of a malicious server, or able to effect a “man in the middle” attack, could present a malformed SSL/TLS signature from a certificate chain to a vulnerable client and bypass validation.
This update has been rated as having important security impact on FreeBSD, all version of Ubuntu / Debian, Red Hat (RHEL), CentOS, Fedora and other open source operating system that depends upon OpenSSL. [continue reading…]
openSUSE version 11.1 has been released and available for download (jump to download) from the official project website. The 11.1 release includes a ton of new features and improvements, an improved desktop experience with GNOME 2.24 and KDE 4.1.3, OpenOffice.org 3.0, YaST improvements, updated Linux kernel, and much more. [continue reading…]
Good news for all holiday buyers and open source software supporters.
HP today announced its plans to introduce Linux as an operating system choice for business desktop customers. After Dell, HP the leader in worldwide Linux server shipments and revenue, has introduced a new desktop offering with SUSE Linux Enterprise Desktop from Novell on the HP Compaq dc5850. The offerings are designed to help small businesses enhance their productivity and ease their management of technology. You will get productivity software like: [continue reading…]
fold is really nifty command line utility to make a text file word wrap. This is useful for large number of text files processing. There is no need to write a perl / python code or use a word processor.
fold command syntax
fold -sw {COUNT} {input.txt} > {output.txt}
Wrap input lines in each input.txt, writing to standard output.txt.
Where,
-s: break at spaces
-w: {COUNT} use COUN} as WIDTH columns instead of default 80.
For example, following command will wrap input.txt at 60 width columns: $ fold -sw 60 input.txt > output.txt
A large number of files can be processed using for shell loop:
