The first thing that you will notice about Linux Red Hat (using the Gnome Interface) is that it looks a lot like Windows 95/98/NT. But that's where the similarity ends. Linux requires a whole new set of commands as well as a new way of thinking about things.
For instance, in Windows 95/98 you can adjust monitor or screen properties by just a few key strokes. With Linux, however, in order to adjust the monitor settings, you have to run a program called Xconfigurator. And there is no information anywhere as to how to do this. It is one of these secret things that Linux users don't worry about because "everyone knows how to do it". Those of us changing from Windows to Linux have a need to know these things.
Let me tell you the secret: You have to be logged in as "Root" then you exit to the terminal. Now this looks like a DOS shell, so Windows users don't get too confused. Then at the # prompt type in Xconfigurator. Then you are taken to a configuration program that requires you know a lot about your monitor and your video card. Most of that information is found in the users manual for the hardware, or from the manufacturer. You will need to know the name, model number and manufacturer of the video card and the monitor and you will need to know the refresh rate and vertical and horizontal frequency of the monitor. Be sure that you have this information before you start. After that, you just fill out the form and follow the instructions, it's that simple from there on.
Another well kept secret is that you need to exit to the terminal in order to run any program that does not have an icon on the desktop. That's anything that doesn't specifically come with Red Hat. Some programs will set themselves up with an icon if they are installed in the right desktop interface. Linux has several different desktop interfaces, which is really cool. Gnome is a very Windows like one. The only draw back to Gnome is that some programs like StarOffice won't put an icon on the Gnome interface. So the user gets to do it.
The first thing you need to do is find the executable file for StarOffice, this would be a file called "soffice". The best way to find it is to use the File Manager to locate it. Then make a note of the path and go to Panel and then New Launcher.
Type in the name of the program, e.g. Star Office in the Name field. Then in Comment field put in the text that will appear when the mouse hovers on the icon. Next in Command field type the full path to the program, e.g. /home/jerry/Office51/bin/soffice. Last, choose an icon by clicking on the "No Icon Button", or leave it with no icon. Click on OK and the icon appears on your panel (which resembles the taskbar in Windows).
Linux is not as hard as it would appear at first. Although, they try to tell you that it's really easy, that's not entirely true either. If you know Unix, it's easy. If you know Windows, it's a little hard at first, but then it makes sense. If you are new to computers then Linux is a good program to learn first, because it is so configurable and versatile. There is no end to the possibilities with Linux.
Arlene Mason is a technical writer living in Dallas, Texas. She had been writing on various subjects for many years and says that writing keeps her sane. Most people agree. Please visit http://www.angelfire.com/tx/ElectronicAlchemy for information about her current projects and other news.
Article Source: EzineArticles.com
Linux Secrets
Implementation of Asterisk in Corporate Environments
Asterisk, complete PBX software, runs on Linux, Windows, BSD and OS X. Asterisk does VoIP in four different protocols, and is able to interconnect with almost all telephony equipment which is inexpensive.
Asterisk provides many features like Voicemail services with Directory, Call Conferencing, Interactive Voice Response, and Call Queuing. It includes three-way calling, caller ID services and Skinny.
You will not need additional hardware to implement Asterisk. But it does expect a non-standard driver that implements dummy hardware as a non-portable timing mechanism. Single or multiple VoIP Providers can be used for incoming and outgoing calls, though incoming calls can be handled by different VoIP Providers.
For use of digital and analog telephony equipment, Asterisk supports a number of equipment most notably is Asterisk sponsored hardware Digium. Their FXO and FXS cards are popular for small installations.
Full features of Asterisk Open Source Edition include Full PBX Capability, Switched or Packet Data, VoIP Capability, TDM Capability, Converged Telephony, Voice Mail, Unlimited-Seat Conference Bridge, SIP and IAX Support and Asterisk-centric Poundkey Linux.
Asterisk also includes the Business Edition, where it includes other features like Asterisk Technical Manual, Quick-start Guide, Commercial License with Legal Protection, 240 Simultaneous Calls, Tech Support for Install and Bug Resolution, Free Upgrades and Tech Support for One Year, Access to Business Edition Portal for One Year, Special Offers for Partner Products and many others.
Asterisk allows people to communicate using the internet. It is one of the cheapest ways to talk. The PC clients connect to each other through an Asterisk server which uses a Linux/Unix OS. Asterisk calls are passed through different channel protocols. The most popular forms of calls are H323, SIP, IAX or Zap. Depending on the type of channel you use, the user must have the appropriate software to handle the call type.
Let’s say, if are a registered on an Asterisk PBX (or other PBX) as a SIP user, you are required to use a SIP phone client such as X-Lite or SIPPS. Or, if you are registered as an IAX user you must use an IAX phone client such as iaxcomm. SIP/IAX Client Configuration allows you to register SIP and IAX users. This includes the adjustment of all Asterisk and client phone settings. To make calls with Asterisk telephone system you should connectivity to an Asterisk PBX for call handling and users using PCs with SoftPhones for calling internally and externally. All configuration information for the Asterisk PBX knows is written to the conf files located in /etc/asterisk.
All information for SIP users is stored in sip.conf and for IAX users in iax.conf. Numbers are read from extensions.conf. Voicemails are stored in voicemail.conf etc. To place a call through Asterisk, registration to Asterisk is not required. However, you do need a username and password which will allow you to call someone who is registered. To receive a call, you must be a registered user and have an extension.
When any change is made in conf files from /etc/asterisk/ or changes that relate with some of these files, you must type 'reload' in the Asterisk Command Line Interface (CLI) to make the changes effective.
It is possible to implement only the Open Source Edition for your corporate business. You will only need a Linux OS computer and Asterisk has to be installed.
Article contributed by Phil Lam who is a VoIP consultant at Lantone Communications. Led by a team of experienced IT developers, Lantone Communications is one of the leading VoIP Provider in Singapore. Please visit their official website for the latest information on VoIP.
Article Source: http://www.ArticleBiz.com
More Information on Firewalls
It seems nowadays if you are not online, you don’t exist. It really does not matter what type of company you run, you should have an online presence to let your prospects and clients know about your company and services. When you decide to take the leap onto the Internet there are some precautions you should take. I have friends who say all the time, I really have nothing to hide or worry about. This may be true, but malicious users like to deface websites.Which can ruin you and your businesses reputation.
This is a paper about firewalls protecting your company from outside threats and unauthorized access.
A firewall is a great start. Firewalls can be both hardware and software based. There are many different firewall vendors some of the bigger names are Cisco, Symantec, and Checkpoint. The difficult part is configuring the firewall. This is where many intruders bypass security, because the firewall is poorly configured.
I would like to mention that there are many Open Source programs and operating systems that offer great firewall software. I personally believe that OpenBSD has one of the most secure operating systems and firewall configurations if done right. FreeBSD also has firewall software, it is called IPTABLES.IPTABLES offers packet filtering, NAT and you can even change packets in Linux. I have to say you can do anything you want in Linux, because the source code is right there. It’s a beautiful thing. Linux also uses this; you can build a firewall with the old system sitting in your garage and two Linux compatible network cards.Linux can be hardened, this means to make the operating system more secure. I like the tool Bastille Linux its is developed by Jeff Beale. To really get a grasp on firewalls you need to understand TCP/IP and allot of different protocols to know if you should allow or deny them into your network. IP addresses identify hosts on the Internet they look like this 127.214.234.54. Firewalls can block IP addresses, ports, protocols and even keywords that come into packets. Hackers that want into you network have many different tools at their disposal to try to bypass firewalls. One common attack is known as Denial Of Service or DOS attacks. The attacker simply floods your network, firewalls with so many packets that it cannot handle them and sometimes crashes. Firewalls are available with DOS filtering to keep these attacks low, and start dropping packets.
Firewalls do not protect you from internal threats such as employees bringing in viruses from home. Or remote users using VPN's (virtual Private Networks) bypassing your firewall. Think about if you bring your son to work and he downloads music on your fast company internet connection only to introduce your corporate network with a worm or even worst a Trojan horse. Service ports that are open to the public such as Port 80 HTTP, have know vulnerabilities on the Internet. FTP has many vulnerabilities as well.
Are there different types of firewalls?
Yes. There are hardware and software firewalls. You might be even using Zone Alarm or Black Ice Defender. These are software based firewalls, the more I study firewall technology I realize that everything truly is a software firewall. A computer is nothing without software to tell it what to do.
Packet Filters
Packet Filters look at source and destination addresses. This is where firewall rule sets come in to play. The firewall administrator must determine which source and destination ports and addresses to allow or deny. The security administrator needs to keep up to date with alerts on vulnerabilities as new holes are found and created daily. A technique known as spoofing can sometimes fool firewalls but making it appear that a packet is coming from inside the protected network when in fact it is an attacker changing the source address.
Application Gateways
Application Gateways are like errand boys. You request a file and the application gateway grabs it for you.This is great for logging connections, and setting up authentication as well.
Statefull Packet Inspection
Statefull Packet Inspection is a technique used by Cisco PIX firewalls and Checkpoint Firewalls these firewalls look at the data coming across the network.It can also authenticate connections, users can usually not notice that the firewall is in place. Allot of firewalls now allow you to configure VPN's which is awesome if you have remote workers and satellite offices and need to transfer data securely.
Intrusion Detection is also something to consider, I like SNORT. SNORT can detect known attacks against your system and does a great job at logging them if set up correctly. There are thousands of different software and hardware solutions you can purchase for you home or network. I happen to like Open Source, because I like learning and knowledge and the Open Source community has taught me more than the corporate world ever will. A book I would like to recommend that is great for learning firewalls is called simply enough Building Internet Firewalls, it is by O'reilly. That is all for now. One last tip, backup, backup, backup.
Benjamin Hargis CEO MCP Phuture Networks http://www.phuturenetworks.com
"Article provided by ArticleWorld.net"
How To Control The Way Linux Starts Up: GUI or Command Line Interface
If you were interested in learning linux, one of the main reasons was learning how to work using Linux Shell environment. That is the Command Line Interface ( CLI).
How Did I know?. It happened to me, and the most asked Question is how to access the Command line in Linux.
The trick is let Linux starts with the Linux shell is simple, If done during the installation.
After the installation is over, there might be a way which is Very complex and not intended for beginners or intermediate Linux users.
The good thing is that you can access the Linux Shell whether Your systems starts up with the GUI ( graphic user interface ) Or the Command line Interface ( CLI). I will Explain this later in this article.
Depending on the preference of a users, some prefer their Linux operating system to start with GUI, and others want it to Start up with the Command Line Interface.
If you need your computer to startup linux with the command line, you need to decide during the installation.
During the installation process, you will be prompted to choose the options on starting your linux with the command line Interface, or the GUI (Graphic User Interface).
All what you do is click inside a circle that corresponds to the Command or the GUI, depending on which you prefer.
If after installation you found out that you ended up with an Option you don't want, Command line interface or GUI, you Don't have to go through a reinstall or delete of Your Linux Operating System.
Here is the solution:
Some users are under the impression that, if you installed GUI, you can't access the command line.
Others think, if they have the option of the Command Line Interface, you can't access the GUI.
The above two notions are wrong. It doesn't matter what king Of installation option you have, you can always access both ( CLI and GUI) on you Linux Computer.
Here is how you do it:
1-If you are presented with the command line after Linux boots, And after you login and end up at the command line prompt, you Type:
STARTX
The above command start up the GUI from the command line, and Get you in the Graphic GUI environment of Linux.
2-If you Linux computer start up with the GUI, and you are Taken to the desktop environment, there is a way to access the Linux command line.
From your desktop, you can go trough the startup menu and choose the " TERMINAL", and this will let you access the Command line. You will end you with a windows with the Command prompt from within the desktop.
In summary, accessing the command line interface or the GUI Can both be done on your Linux computer, wether your system is Setup to start with the Shell interface or the GUI.
Thank, George Chamoun 04-25-06
Finally! A Quick and Easy instructional guide by George Chamoun that shows you how to install RedHat Linux operating system on your Windows XP computer without spending outrageous fees for computer technical support. Click the link ==>http://www.dualbootguide.com
George Chamoun
Article Source: EzineArticles.com
Configuring NTP on a LINUX Server
The Network Time Protocol was originally developed to overcome time synchronisation issues on the Internet. NTP is an Internet protocol designed to synchronise network time clients with an accurate time source or reference. NTP defines algorithms and protocol messages to aid the synchronisation of network time clients. This article provides information on how to install and configure the publicly available NTP software distribution. It also shows how to synchronise time with an Internet based time reference.
Internet based NTP time server systems fall into two categories: primary and secondary reference servers. Primary reference servers utilise a highly accurate external timing reference, such as GPS or radio clocks, to provide precise time. Secondart reference servers synchronise their time with primary reference servers and therefore offer slightly reduced accuracy. Primary reference time servers are stratum one servers, while secondary servers have a stratum greater than one.
The NTP source code is freely downloadable under the GNU public license from the NTP web site at 'ntp.org'. NTP was originally developed for the LINUX operating system, however, a port to Windows NT is also available. Once the source code has been obtained, it should be installed, compiled and configured on the host computer. This process is automated with the installation and configuration scripts supplied in the distribution. Many Linux based operating systems have the NTP package pre-installed. However, it may be wise to download the most recent version, which is currently 4.2.4.
The NTP daemon is configured via a configuration file 'ntp.conf'. This configuration file may contain a list of public NTP server references that can be used by the host to synchronise time. The 'server' command can be used to specify public NTP time references, characters specified after the # symbol are comments:
server time-a.nist.gov # Public NTP server: NIST, Gaithersburg, Maryland server time-c.timefreq.bldrdoc.gov # Public NTP Server: NIST, Boulder, Colorado
When the configuration file is complete the NTP daemon can be started using the 'ntpd start' script. Other scripts are vailable that can be used to control the daemon: 'ntpd stop', 'ntpd restart'. There is also a query script available that shows the current synchronisation status of the daemon: 'ntpq -p'.
The 'restrict' command can be used to control access premissions to the NTP server. There are a number of permutations or the 'restrict' command; a few examples are listed below.
restrict default ignore #Restrict all access to the time server restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap # Only allow local computers access
Multiple commands can be specified to restrict or disallow access to a range of computers.
NTP provides an additional level of security by utilising authentication codes. This is a mechanism where matching key codes can be specified on a client and server which are encrypted and passed between the server and client. This allows a client to confirm the source of a time message. Authentication keys are configured in the 'ntp.keys' file. They are specified using a key reference, encryption code and authentication key. Additionally, trusted authentication keys can be specified using the 'trusted key' command is the 'ntpd.conf' configuration file.
Try setting Fetchmail with TLS
My Office have single account in Provider for poll email.... I want to try use fetchmail to get that emails and to deliver local account .... wait for next news ... googling the net for that ...
Nvu Installation in fedora ... weird
I want to develop my office website. Based on review, i try to use nvu in my Fedora. Installation process is perfect.
But nvu can not run... I try to answer to Howforge
Success !
Finally ... my fedora is running smoothly ... include Postfix, fetchmail, dovecot, sasauth, squid, squidGuard etc... : )
Fedora 7 - Next Installation
This morning. I try to setup Postfix with TLS. And then try to setup Squid, SquidGuard and Fetchmail for my office need. But I have some problem with my Yum. There is some errorneous/fail to update repository.
Now I try to clean yum Db with this command:
# yum clean all
# yum update