Pages

Thursday, September 16, 2010

How to configure sendmail server in linux

first configure following :-
  • A linux client with ip address 192.168.0.2 and hostname Client1
  • A Configured DNS server
  • A linux server with ip address 192.168.0.1 and hostname Server
  • on Linux server
  • Updated /etc/hosts file on both linux system
  • Running portmap and xinetd services
  • Firewall should be off on server
                               NOW CONFIGURE SEND MAIL SERVER

FIRST OF ALL INSTALL PACKAGE:-


open /etc/mail/sendmail.mc for editing
show hidden line with : set nu option on vi command mode
By default, the following line limits sendmail access to connect local host only [line no 116] 
comment this line with dnl keyword followed by # sign

Now generate new sendmail.cf file by using m4 command as shown here 
     M4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf  

Now restart sendmail service and also set it on with chkconfig

IT SHOULD BE RUN SUCCESSFULLY .

              NOW CONFIGURE SENDMAIL CLIENT

Check sendmail and m4 rpm for install. Open /etc/mail/sendmail.mc file and locate line no 116 and put a dnl with # sing and save file. All step are same which you have done on server.
Now generate new sendmail.cf file by using m4 command as shown here
  M4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf 

Now restart sendmail service and also set it on with chkconfig

Testing of sendmail server

We will test sendmail server by sending and receiving mail in lab environment. for this we use two user one on each system. Now create one user on each system . server and client .

Now send mail from server user toclient user and client user to server user  and also check each others mail by mail command

Use full user name to send mail. For example to send mail to server user use serveruser@server.example.com and to send mail to client user clientuser@example.com



Sunday, March 28, 2010

DIFFERENCE BETWEEN KDE AND GNOME

KDE  (K Desktop Environment)  and Gnome (GNU Network Object Model Environment)  are two graphical user interfaces that are available for Linux. Both are Desktop environment .

Summary:
1. KDE and Gnome are two graphical user interfaces that are available for Linux
2. KDE uses the QT toolkit while Gnome uses the GTK+ toolkit
3. KDE and Gnome are not hard coded into any Linux distribution like the Windows UI is
4. The difference between these two are mainly cosmetic and it doesn’t really affect the functionality of the Linux distro
5. Users are often put-off by the complexity of KDE while Gnome keeps it clean and simple

U Can understand both by following images





http://www.cyberciti.biz/tips/wp-content/uploads/2006/11/kde.gif
KDE DESKTOP


WHAT IS FEDORA

Fedora (pronounced /fəˈdɔrə/) is an RPM-based, general purpose operating system built on top of the Linux kernel, developed by the community-supported Fedora Project and sponsored by Red Hat. The Fedora Project's mission is to lead the advancement of free and open source software and content as a collaborative community.[2]
One of Fedora's main objectives is not only to contain software distributed under a free and open source license, but also to be on the leading edge of such technologies.[3][4] Fedora developers prefer to make upstream changes instead of applying fixes specifically for Fedora—this ensures that their updates are available to all GNU/Linux distributions.[5]
Fedora has a comparatively short life cycle: version X is maintained until one month after version X+2 is released. With 6 months between releases, the maintenance period is about 13 months for each version.[6]
Linus Torvalds, author of the Linux kernel, says he uses Fedora because it had fairly good support for PowerPC when he used that processor architecture. He became accustomed to the operating system and continues to use it (as of 2008).[7]
According to Distrowatch, Fedora is the second most popular GNU/Linux-based operating system as of early 2010, behind Ubuntu.[8]

Thursday, March 25, 2010

Top Ten LINUX Distributions

UbuntuThe launch of Ubuntu was first announced in September 2004. Although a relative newcomer to the Linux distribution scene, the project took off like no other before, with its mailing lists soon filled in with discussions by eager users and enthusiastic developers. In the few years that followed, Ubuntu has grown to become the most popular desktop Linux distribution and has greatly contributed towards developing an easy-to-use and free desktop operating system that can compete well with any proprietary ones available on the market.

Ubuntu



















                                               Ubuntu 9.10
 Fedora
 Although Fedora was formally unveiled only in September 2004, its origins effectively date back to 1995 when it was launched by two Linux visionaries -- Bob Young and Marc Ewing -- under the name of Red Hat Linux. The company's first product, Red Hat Linux 1.0 "Mother's Day", was released in the same year and was quickly followed by several bug-fix updates. In 1997, Red Hat introduced its revolutionary RPM package management system with dependency resolution and other advanced features which greatly contributed to the distribution's rapid rise in popularity and its overtaking of Slackware Linux as the most widely-used Linux distribution in the world. In later years, Red Hat standardised on a regular, 6-month release schedule.



Fedora
                                              Fedora 12
 openSUSEhe beginnings of openSUSE date back to 1992 when four German Linux enthusiasts -- Roland Dyroff, Thomas Fehr, Hubert Mantel and Burchard Steinbild -- launched the project under the name of SuSE (Software und System Entwicklung) Linux. In the early days, the young company sold sets of floppy disks containing a German edition of Slackware Linux, but it wasn't long before SuSE Linux became an independent distribution with the launch of version 4.2 in May 1996. In the following years, the developers adopted the RPM package management format and introduced YaST, an easy-to-use graphical system administration tool. Frequent releases, excellent printed documentation, and easy availability of SuSE Linux in stores across Europe and North America resulted in growing popularity of the distribution.
 openSUSE
                                             OPENSUSE 11.2
 Debian GNU/Linux
 Debian GNU/Linux was first announced in 1993. Its founder, Ian Murdock, envisaged the creation of a completely non-commercial project developed by hundreds of volunteer developers in their spare time. With sceptics far outnumbering optimists at the time, it was destined to disintegrate and collapse, but the reality was very different. Debian not only survived, it thrived and, in less than a decade, it became the largest Linux distribution and possibly the largest collaborative software project ever created!
Debian GNU/Linux




                                  















                                              Debian GNU/Linux 5.0

Mandriva Linux


 Mandriva Linux was launched by Gaël Duval in July 1998 under the name of Mandrake Linux. At first, it was just a re-mastered edition of Red Hat Linux with the more user-friendly KDE desktop, but the subsequent releases also added various user-friendly touches, such as a new installer, improved hardware detection, and intuitive disk partitioning utility. As a result of these enhancements, Mandrake Linux flourished. After attracting venture capital and turning into a business, the fortunes of the newly established MandrakeSoft fluctuated widely between a near bankruptcy in early 2003 to a flurry of acquisitions in 2005. The latter, after merging with Brazil's Conectiva, saw the company change its name to Mandriva.



Mandriva Linux

                                             Mandriva Linux 2010
Linux Mint Linux Mint, a distribution based on Ubuntu, was first launched in 2006 by Clement Lefebvre, a French-born IT specialist living and working in Ireland. Originally maintaining a Linux web site dedicated to providing help, tips and documentation to new Linux users, the author saw the potential of developing a Linux distribution that would address the many usability drawbacks associated with the generally more technical, mainstream products. After soliciting feedback from the visitors on his web site, he proceeded with building what many refer to today as an "improved Ubuntu".

 Linux Mint
                                          Linux Mint 8

PCLinuxOS 
 PCLinuxOS was first announced in 2003 by Bill Reynolds, better known as "Texstar". Prior to creating his own distribution, Texstar was already a well-known developer in the Mandrake Linux community of users for building up-to-date RPM packages for the popular distribution and providing them as a free download. In 2003 he decided to build a new distribution, initially based on Mandrake Linux, but with several significant usability improvements. The goals? It should be beginner-friendly, have out-of-the box support for proprietary kernel modules, browser plugins and media codecs, and should function as a live CD with a simple and intuitive graphical installer.
PCLinuxOS









 PCLinuxOS 2009.2











                         PCLinuxOS 2009.2

Slackware Linux
Slackware Linux, created by Patrick Volkerding in 1992, is the oldest surviving Linux distribution. Forked from the now-discontinued SLS project, Slackware 1.0 came on 24 floppy disks and was built on top of Linux kernel version 0.99pl11-alpha. It quickly became the most popular Linux distribution, with some estimates putting its market share to as much as 80% of all Linux installations in 1995. Its popularity decreased dramatically with the arrival of Red Hat Linux and other, more user-friendly distributions, but Slackware Linux still remains a much-appreciated operating system among the more technically-oriented system administrators and desktop users.
Slackware Linux
                                  Slackware Linux 13.0
 Gentoo LinuxThe concept of Gentoo Linux was devised in around the year 2000 by Daniel Robbins, a former Stampede Linux and FreeBSD developer. It was the author's exposure to FreeBSD and its "autobuild" feature called "ports", which inspired him to incorporate some of the FreeBSD software management principles into Gentoo under the name of "portage". The idea was to develop a Linux distribution that would allow users to compile the Linux kernel and applications from source code directly on their own computers, thus maintaining a highly-optimised and always up-to-date system. By the time the project released its 1.0 version in March 2002, Gentoo's package management was considered a superior alternative to some binary package management systems, especially the then widely-used RPM.

 Gentoo Linux


 CentOSLaunched in late 2003, CentOS is a community project with the goals of rebuilding the source code for Red Hat Enterprise Linux (RHEL) into an installable Linux distribution and to provide timely security updates for all included software packages. To put in more bluntly, CentOS is nothing more than a clone of RHEL. The only technical difference between the two is branding - CentOS replaces all Red Hat trademarks and logos with its own. But the connection between RHEL and CentOS is not immediately visible on the CentOS web site; due to trademark laws, Red Hat is referred to as a "Prominent North American Enterprise Linux Vendor", instead of its proper name. Nevertheless, the relations between Red Hat and CentOS remain amicable and many CentOS developers are in active contact with Red Hat engineers.
 CentOS
                                                      CentOS 5.4
 FreeBSDFreeBSD, an indirect descendant of AT&T UNIX via the Berkeley Software Distribution (BSD), has a long and turbulent history dating back to 1993. Unlike Linux distributions, which are defined as integrated software solutions consisting of the Linux kernel and thousands of software applications, FreeBSD is a tightly integrated operating system built from a BSD kernel and the so-called "userland" (therefore usable even without extra applications). This distinction is largely lost once installed on an average computer system - like many Linux distributions, a large collection of easily installed, (mostly) open source applications are available for extending the FreeBSD core, but these are usually provided by third-party contributors and aren't strictly part of FreeBSD.
 FreeBSD
                                                     FreeBSD 8.0

LINUX KERNEL

In computing, the kernel is the central component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources (the communication between hardware and software components).[1] Usually as a basic component of an operating system, a kernel can provide 

The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems.[6] It is one of the most prominent examples of free and open source software.[7]
The Linux kernel is released under the GNU General Public License version 2 (GPLv2),[4] plus controversial proprietary licenses for some firmware images, and is developed by contributors worldwide. Day-to-day development takes place on the Linux kernel mailing list.
The Linux kernel was initially conceived and created by Finnish computer science student[8] Linus Torvalds in 1991. Linux rapidly accumulated developers and users who adopted code from other free software projects for use with the new operating system.[9] The Linux kernel has received contributions from thousands of programmers.[10] Many Linux distributions have been released based upon the Linux kernel.

WHAT IS GNU

GNU computer operating system composed entirely of free software.  This name was chosen because GNU's design is Unix-like, but differs from Unix by being free software and containing no Unix code. Development of GNU was initiated by Richard Stallman and was the original focus of the Free Software Foundation (FSF).

GNU is developed by the GNU Project, and programs released under the auspices of the project are called GNU packages or GNU programs. The system's basic components include the GNU Compiler Collection (GCC), the GNU Binary Utilities (binutils), the bash shell, the GNU C library (glibc), and GNU Core Utilities (coreutils).
GNU is in active development. Although nearly all components were completed long ago and have been in production use for a decade or more, its official kernel, GNU Hurd, is incomplete. Thus, the third-party Linux kernel is most commonly used instead. While the Linux kernel was not originally developed for the sake of the GNU project, GNU developers have contributed Linux ports of GNU applications and utilities, which are now also widely used on other operating systems such as BSD variants, Solaris and Mac OS X.
The GNU General Public License (GPL), the GNU Lesser General Public License (LGPL), and the GNU Free Documentation License (GFDL) were written for GNU, but are also used by many unrelated projects.

WHAT IS MINIX

MINIX is a Unix-like computer operating system based on a microkernel architecture. Andrew S. Tanenbaum wrote the operating system to be used for educational purposes; MINIX also inspired the creation of the Linux kernel. Its name is a portmanteau of the words minimal and Unix.
MINIX has been free and open source software since it was released under the BSD license in April 2000.

BRIEF HISTORY OF LINUX

Linux was developed by Linus Torvalds in 1991.
In 1991, in Helsinki, Linus Torvalds began a project that later became the Linux kernel. It was initially a terminal emulator, which Torvalds used to access the large UNIX servers of the university. He wrote the program specifically for the hardware he was using and independent of an operating system because he wanted to use the functions of his new PC with an 80386 processor. Development was done on MINIX using the GNU C compiler, which is still the main choice for compiling Linux today (although the code can be built with other compilers, such as the Intel C Compiler).[citation needed]
As Torvalds wrote in his book Just for Fun[7], he eventually realized that he had written an operating system kernel. On 25 August 1991, he announced this system in a Usenet posting to the newsgroup "comp.os.minix.":[8]
“ Hello everybody out there using minix -
I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones. This has been brewing since april, and is starting to get ready. I'd like any feedback on things people like/dislike in minix, as my OS resembles it somewhat (same physical layout of the file-system (due to practical reasons) among other things).
I've currently ported bash(1.08) and gcc(1.40), and things seem to work. This implies that I'll get something practical within a few months, and I'd like to know what features most people would want. Any suggestions are welcome, but I won't promise I'll implement them :-)
Linus (torvalds@kruuna.helsinki.fi)
PS. Yes – it's free of any minix code, and it has a multi-threaded fs. It is NOT portable (uses 386 task switching etc), and it probably never will support anything other than AT-harddisks, as that's all I have :-(.

BRIEF HISTORY OF UNIX

Unix is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas Mcllroy, and Joe Ossanna. Today the term "Unix" is commonly used to describe any operating system that conforms to Unix standards, meaning the core operating system operates similarly to the original Unix operating system. Today's Unix systems are split into various branches, developed over time by AT&T as well as various commercial vendors and non-profit organizations.

Wednesday, March 24, 2010

Exam Preparation

there is two track of certification
standard track

The Standard Track consists of three courses -- RH033, RH133, RH253 -- and is aimed at persons who need more review of key concepts or who are new to both UNIX and Linux.
RH033 Red Hat Linux Essentials targets IT professionals with no prior UNIX or Linux experience, and covers skills to prepare for RH133, including shell and command line essentials.
RH133 Red Hat linux Administration are designed for those wanting to prepare for professional responsibilities as a Linux systems administrator at the Technician level. You'll learn all the skills required to manage a Linux workstation and attach it to a corporate network, including configuration of client-side network services. Prerequisites include networking fundamentals and internetworking with TCP/IP, widely available from reputable training vendors or through self-study. RH133 includes the RHCT Exam on the last day.

RH253 Red Hat Linux Networking and Security Administration is designed for those who desire to build skills at configuring and administering a Red Hat Linux server running key enterprise network services and security. Prerequisites include RH133 or equivalent skills.

repid track

The Rapid Track consists of one course -- RH300 Red Hat Rapid Track Course (and RHCE Exam) -- and is aimed at persons who are experienced UNIX and Linux users, networking specialists, and system administrators and need specific Red Hat Enterprise Linux training to pass the RHCE Exam (which is included).

Courses you should take:

RH033 Red Hat Linux Essentials
RH131 Red Hat System Administration
or
RH133 Red Hat Linux Administration (and RHCT Exam)
RH253 Red Hat Linux Networking and Security Administration

The RHCE Exam

Becoming a Red Hat Certified Engineer requires passing a 3.5 hour hands-on exam. There are four different approaches to preparing for the exam depending on your existing level of Linux expertise.


The RHCE certification (Red Hat Certified Engineer) is Red Hat’s most widely known, and widely respected, Linux qualification. The hands-on nature of the exam coupled with its perceived difficulty has gone a long way to making the RHCE credential something worth having and something employers are increasingly aware of.

In order to gain the RHCE certification candidates must successfully pass a full-day, hands-on performance-based exam, RH302, consisting of two distinct sections:



To pass and gain the RHCE certification credential, candidates must meet all of the following:


  • Achieve a score of 80 or higher on Section I, consisting of compulsory and optional problems;
  • Successful completion of the Section I compulsory troubleshooting problems within one hour of that section's start time;
  • Achieve 70 percent or more on the RHCT-level skills in Section II;
  • Achieve 70 percent or more on the RHCE-level skills in Section II.

Candidates will be e-mailed their results within three US business days along with a digital certificate if successful.

It is possible to fail the RHCE exam yet still gain the lower-level RHCT certification by successfully completing the sections of the exam that are tied to the RHCT competencies. In such situations, candidates will still be required to pass the complete RCHE exam if they wish to retake the exam and become RHCE qualified. A candidate may retake the exam as many times as they wish upon payment of the applicable exam fees.

Because the RHCE is lab-based, exams can only be taken at Red Hat authorized facilities (consult the Red Hat website for information on facilities in your area) and only during specific times. This is something that should be considered when factoring the total cost of obtaining the RHCE credential as travel costs could be quite significant depending on your location. Candidates may not take notes or other materials into the testing area.

For those who require formal training, Red Hat offer training courses both online and offline to help candidates prepare for the RHCE exam. Red Hat offer various training and exam packages depending on the level of experience a candidate already has, including a ‘success package’ which comprises a training course as well as two attempts at the exam (according to Red Hat, less than 50% of first-time takers pass the RHCE exam, with the success rate climbing to around 75% on the second attempt).

As with all Red Hat certifications, RHCE qualified individuals are considered current for the life of the release under which the qualification was earned so a candidate’s RCHE qualification will expire at some point in the future – another cost factor that needs to be considered if a candidate wishes to stay current. Recertification requires taking the current version of the RH302 exam again as there is no ‘upgrade’ exam.

WHAT IS RHCE

Red Hat Certified Engineer (RHCE) is a performance-based test that measures actual competency on live systems. Called the "crown jewel of Linux certifications," RHCE proves an individual's ability to configure networking services and security on servers running a Red Hat OS. RHCE was recently named the hottest certification in all of IT by CertCities.com.