Saturday, April 4, 2009


A firewall is an integrated collection of security measures designed to prevent unauthorized electronic access to a networked computer system. It is also a device or set of devices configured to permit, deny, encrypt, decrypt, or proxy all computer traffic between different security domains based upon a set of rules and other criteria.
A system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.
There are several types of firewall techniques:
Packet filter: Looks at each packet entering or leaving the network and accepts or rejects it based on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to configure. In addition, it is susceptible to IP spoofing.
Application gateway: Applies security mechanisms to specific applications, such as FTP and Telnet servers. This is very effective, but can impose a performance degradation.
Circuit-level gateway: Applies security mechanisms when a TCP or UDP connection is established. Once the connection has been made, packets can flow between the hosts without further checking.
Proxy server: Intercepts all messages entering and leaving the network. The proxy server effectively hides the true network addresses.

Wednesday, April 1, 2009

( Reference
Red Hat, Inc. (NYSE: RHT) is a company in the free and open source software sector, and a major Linux distribution vendor. Founded in 1995, Red Hat has its corporate headquarters in Raleigh, North Carolina with satellite offices worldwide.
Red Hat has become associated to a large extent with its enterprise operating system Red Hat Enterprise Linux and with the acquisition of open-source enterprise middleware vendor JBoss. Red Hat provides operating-system platforms along with middleware, applications, and management products, as well as support, training, and consulting services.

<<<--- GOING PAST :
In 1993 Bob Young incorporated the ACC Corporation, a catalog business that sold Linux and UNIX software accessories. In 1994 Marc Ewing created his own Linux distribution, which he named Red Hat Linux. Ewing released it in October, and it became known as the Halloween release. Young bought Ewing's business in 1995, and the two merged to become Red Hat Software, with Young serving as chief executive officer (CEO).
Red Hat went public on August 11, 1999, the eighth-biggest first-day gain in the history of Wall Street.[5] Matthew Szulik succeeded Bob Young as CEO in November of that year.

On November 15, 1999, Red Hat acquired Cygnus Solutions. Cygnus provided commercial support for free software and housed maintainers of GNU software products such as the GNU Debugger and GNU Binutils. One of the founders of Cygnus, Michael Tiemann, became the chief technical officer of Red Hat and by 2008[update] the vice president of open source affairs. Later Red Hat acquired WireSpeed, C2Net and Hell's Kitchen Systems.
In February 2000, InfoWorld awarded Red Hat its fourth consecutive "Operating System Product of the Year" award for Red Hat Linux 6.1. Red Hat acquired Planning Technologies, Inc in 2001 and in 2004 AOL's iPlanet directory and certificate-server software.
Red Hat moved its headquarters from Durham, NC, to N.C. State University's Centennial Campus in Raleigh, North Carolina in February 2002. In the following month Red Hat introduced the first enterprise-class Linux operating system: Red Hat Advanced Server, later re-named Red Hat Enterprise Linux (RHEL). Dell, IBM, HP and Oracle Corporation announced their support of the platform.
In December 2005 CIO Insight magazine conducted its annual "Vendor Value Survey", in which Red Hat ranked #1 in value for the second year in a row. Red Hat stock became part of the NASDAQ-100 on December 19, 2005.
Red Hat acquired open-source middleware provider JBoss on June 5, 2006 and JBoss became a division of Red Hat. In 2007 Red Hat acquired MetaMatrix and made an agreement with Exadel to distribute its software. On September 18, 2006, Red Hat released the Red Hat Application Stack, the first certified stack integrating JBoss technology. On December 12, 2006, Red Hat moved from NASDAQ (RHAT) to the New York Stock Exchange (RHT).
On March 15, 2007, Red Hat released Red Hat Enterprise Linux 5, and in June acquired Mobicents. On March 13, 2008, Red Hat acquired Amentra, a provider of systems integration services for service-oriented architecture, business process management, systems development and enterprise data services. Amentra operates as an independent Red Hat company.
Utilities and tools :
Over and above Red Hat's major products and acquisitions, Red Hat programmers have produced software programming tools and utilities to supplement standard Unix and Linux software. Some of these Red Hat "products" have found their way from specifically Red Hat operating environments via open-source channels to a wider community. Such utilities include:
1) Disk Druid (for disk partitioning)
2) rpm (for package management)
3) sos (for gathering information on system hardware and configuration)
4) sysreport (gathers system hardware and configuration details)
5) systemtap (tracing tool for linux kernel)
The Red Hat web site has a list of their major involvements in free and open source software projects.