ping icmp open socket Operation not permitted

Ping command not working as other user and getting below error

Error: ping: icmp open socket: Operation not permitted

Solution : 1. Login as Root User
2. cd /bin/
3. type ll you will get like 4th point
4. drwxr-xr-x 2 root root 4096 Aug 25 16:59 /bin
5. If you didnt get this chmod and give permission
6. After this type this below command as Root user
7. chmod u+s ping
8. Finally you will get like this
9. [root@training bin]# ll
-rwsrwxrwx 1 root root 33272 Mar 15 2007 ping
10. Then go to su - sunserver
11. Type ping (IP Address)
64 bytes from sunserver.chainsys.com (192.168.2.221): icmp_seq=0 ttl=64 time=1.36 ms
64 bytes from sunserver.chainsys.com (192.168.2.221): icmp_seq=1 ttl=64 time=0.212 ms
64 bytes from sunserver.chainsys.com (192.168.2.221): icmp_seq=2 ttl=64 time=0.207 ms

Computer Security Tips for Small Business and Home Computer User

Computer Security Tips for Small Business and
Home Computer User

Use strong passwords. Choose passwords that are difficult or impossible to guess.

Give different passwords to all accounts

Make regular backups of critical data. Backups must be made at least once each day. Larger organizations should perform a full backup weekly and incremental backups every day. At least once a month the backup media should be verified

Use virus protection software. That means three things: having it on your computer in the first place, checking daily for new virus signature updates, and then actually scanning all the files on your computer periodically.

Use a firewall as a gatekeeper between your computer and the Internet. Firewalls are usually software products. They are essential for those who keep their computers online through the popular DSL and cable modem connections but they are also valuable for those who still dial in.

Do not keep computers online when not in use. Either shut them off or physically disconnect them from Internet connection.

Do not open email attachments from strangers, regardless of how enticing the Subject Line or attachment may be. Be suspicious of any unexpected email attachment from someone you do know because it may have been sent without that person's knowledge from an infected machine

Regularly download security patches from your software vendors.

Tips for Children
• Do not give out identifying information such as Name, Home Address, School Name or Telephone Number in a chat room.
• Do not send your photograph to any one on the Net without first checking with the parent or guardian.
• Do not respond to messages or bulletin board items that are suggestive, obscene, belligerent or threatening.
• Never arrange a face to face meeting without telling parent or guardian.
• Remember that people online may not be who they seem to be.

Tips for parents

• Use content filtering softwares on your PC to protect children from pornography, gambling, hate speech, drugs and alcohol.
• There are also softwares to establish time controls for individual users (for example blocking usage after a particular time at night) and log surfing activities allowing parents to see which sites the child has visited. Use these softwares.

Protect Yourself and Your PC

• Use the latest version of a good anti-virus software package which allows updations from the Internet.
• Use the latest version of the operating system, web browsers and e-mail programs.
• Don't open e-mail attachments unless you know the source. Attachments, especially executables (those having .exe extension) can be dangerous.
• Confirm the site you are doing business with. Secure yourself against "web- spoofing". Do not go to websites from email links.
• Use hard to guess passwords that contain mixes of numbers and letters. They should not be dictionary words. They should combine upper and lower case characters.
• Use different passwords for different websites.
• Send credit card information only to secure sites
• Use a security program that gives you control over "cookies" that send information back to websites. Letting all cookies in without monitoring them could be risky

Protect Your Website

• Stay informed and be in touch with security related news.
• Watch traffic to your site. Put host-based intrusion detection devices on your web servers and monitor activity looking for any irregularities.
• Put in firewalls.
• Configure your firewalls correctly.
• Develop your web content off line.
• Make sure that the web servers running your public web site are physically separate and individually protected from your internal corporate network. • Protect your databases. If your web site serves up dynamic content from a database, consider putting that database behind a second interface on your firewall, with tighter access rules than the interface to your web server.
• Back up your web site after every updation, so that you can re-launch it, immediately, in case of a malicious defacement

Computer Fundamendals

computer

A programmable machine. The two principal characteristics of a computer are:

It responds to a specific set of instructions in a well-defined manner.

• It can execute a prerecorded list of instructions (a program).

Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.

All general-purpose computers require the following hardware components:

memory : Enables a computer to store, at least temporarily, data and programs.

mass storage device : Allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.

input device : Usually a keyboard and mouse, the input device is the conduit through which data and instructions enter a computer.

output device : A display screen, printer, or other device that lets you see what the computer has accomplished.

central processing unit (CPU): The heart of the computer, this is the component that actually executes instructions.

In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another.

Computers can be generally classified by size and power as follows, though there is considerable overlap:

personal computer : A small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.

workstation : A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.

minicomputer : A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.

mainframe : A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.

supercomputer : An extremely fast computer that can perform hundreds of millions of instructions per second.

Binary

Pertaining to a number system that has just two unique digits. For most purposes, we use the decimal number system, which has ten unique digits, 0 through 9. All other numbers are then formed by combining these ten digits. Computers are based on the binary numbering system, which consists of just two unique numbers, 0 and 1. All operations that are possible in the decimal system (addition, subtraction, multiplication, division) are equally possible in the binary system.

We use the decimal system in everyday life because it seems more natural (we have ten fingers and ten toes). For the computer, the binary system is more natural because of its electrical nature (charged versus uncharged).

In the decimal system, each digit position represents a value of 10 to the position's power. For example, the number 345 means:

3 three 100s (10 to the 2nd power)

plus

4 four 10s (10 to the first power)

plus

5 five 1s (10 to the zeros power)

In the binary system, each digit position represents a value of 2. For example, the binary number 1011 equals:

1 one 8 (2 to the 3rd power)

plus 0 zero 4s (2 to the 2nd power)

plus

1 one 2 (2 to the first power)

plus

1 one 1 (2 to the zeros power)

So a binary 1011 equals a decimal 11.

Because computers use the binary number system, powers of 2 play an important role. This is why everything in computers seems to come in 8s (2 to the 3rd power), 64s (2 to the 6th power), 128s (2 to the 7th power), and 256s (2 to the 8th power). Programmers also use the octal (8 numbers) and hexadecimal (16 numbers) number systems because they map nicely onto the represents four binary digits.

Integrated circuit

Another name for a chip, an integrated circuit (IC) is a small electronic device made out of a semiconductor material. The first integrated circuit was developed in the 1950s by Jack Kirby of Texas Instruments and Robert Noyce of Fairchild Semiconductor.

Integrated circuits are used for a variety of devices, including microprocessors, audio and video equipment, and automobiles. Integrated circuits are often classified by the number of transistors and other electronic components they contain:

SSI (small-scale integration): Up to 100 electronic components per chip

MSI (medium-scale integration): From 100 to 3,000 electronic components per chip

LSI(large-scale integration): From 3,000 to 100,000 electronic components per chip

VLSI (very large-scale integration): From 100,000 to 1,000,000 electronic components per chip

ULSI (ultra large-scale integration): More than 1 million electronic components per chip

semiconductor

A material that is neither a good conductor of electricity (like copper) nor a good insulator (like rubber). The most common semiconductor materials are silicon and germanium. These materials are then doped to create an excess or lack of electrons.

Computer chips, both for CPU and memory, are composed of semiconductor materials. Semiconductors make it possible to miniaturize electronic components, such as transistors. Not only does miniaturization mean that the components take up less space, it also means that they are faster and require less energy

File Size Conversion Table

The table below shows the relationship between the file storage sizes that computers use. Binary calculations are based on units of 1,024, and decimal calculations are based on uints of 1,000. It should be noted that decimal calculations are based on units that have been rounded off to the nearest 1,000 and therefore differ from the actual number of bytes used in binary calculations.

Name	Symbol	Binary Measurement	Decimal Measurement	Number of Bytes	Equal to
kilobyte	KB	2^10	10^3	1,024	1,024 bytes
megabyte	MB	2^20	10^6	1,048,576	1,024KB
gigabyte	GB	2^30	10^9	1,073,741,824	1,024MB
terabyte	TB	2^40	10^12	1,099,511,627,776	1,024GB
petabyte	PB	2^50	10^15	1,125,899,906,842,624	1,024TB
exabyte	EB	2^60	10^18	1,152,921,504,606,846,976	1,024PB
zettabyte	ZB	2^70	10^21	1,180,591,620,717,411,303,424	1,024EB
yottabyte	YB	2^80	10^24	1,208,925,819,614,629,174,706,176	1,024ZB

The Five Generations of Computers

The history of computer development is often referred to in reference to the different generations of computing devices. Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices. Read about each generation and the developments that led to the current devices that we use today.

To this date, there are only four generations of computers, the "fifth generation" is but the name of a Japan's national research project in the 1980's.

First Generation - 1940-1956: Vacuum Tubes

The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions. First generation computers relied on machine language to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.

The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

Second Generation - 1956-1963: Transistors

Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 50s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.

Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.

The first computers of this generation were developed for the atomic energy industry.

Third Generation - 1964-1971: Integrated Circuits

The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

Fourth Generation - 1971-Present: Microprocessors

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer - from the central processing unit and memory to input/output controls - on a single chip.

In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.

As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.

Proposed and Failed "Fifth Generation" - 1982-1993 Massively Parallel Computers

From Wikipedia, "The Fifth Generation Computer Systems project (FGCS) was an initiative by Japan's Ministry of International Trade and Industry, begun in 1982, to create a "fifth generation computer" (see history of computing hardware) which was supposed to perform much calculation utilizing massive parallelism. It was to be the end result of a massive government/industry research project in Japan during the 1980s. It aimed to create an "epoch-making computer" with supercomputer-like performance and usable artificial intelligence capabilities."

Also from Wikipedia, "The term fifth generation was intended to convey the system as being a leap beyond existing machines. ...the fifth generation, it was widely believed at the time, would instead turn to massive numbers of CPUs for added performance."

The project was canceled in 1993 with little appreciable lasting impact.

Oracle Listener Security

Are you Protected from any unauthorized users to start and shutdown your Oracle Listener!!!!!!

Add Oracle Listener Security

By default Listener Configured Without password and unauthorized Users can change the setting of listerner with netca,netmgr command and they can start and shut listener. So you should apply security to your listener.

Step 1:To secure your Listener With Password put this command as your oracle user:
#lsnrctl
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 24-AUG-2010 15:09:32

Copyright (c) 1991, 2005, Oracle. All rights reserved.

Welcome to LSNRCTL, type "help" for information.

LSNRCTL>change_password

Old password: 
New password: 
Reenter new password: 

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)
(HOST=training.hemanth.com)(PO RT=1523)))
Password changed for CHAI10
The command completed successfully

LSNRCTL> save_config
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)
(HOST=training.hemanth.com)(PORT=1523)))
Saved CHAI10 configuration parameters.
Listener Parameter File
/oracle/oracle/product/10.2.0/db_1//network/admin/listener.ora
Old Parameter File
/oracle/oracle/product/10.2.0/db_1//network/admin/listener.bak
The command completed successfully
LSNRCTL>exit



If you are not using the default Listener name do like this
and getting this below error follow this:



LSNRCTL> change_password
Old password:
New password:
Reenter new password:
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
TNS-00511: No listener
inux Error: 111: Connection refused

First you must use this command

LSNRCTL> set cur LISTENER_NAME

LSNRCTL>change_password


Old password: 
New password: 
Reenter new password: 

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)
(HOST=training.hemanth.com)(PO RT=1523)))
Password changed for CHAI10
The command completed successfully

LSNRCTL> save_config
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)
(HOST=training.hemanth.com)(PORT=1523)))
Saved CHAI10 configuration parameters.
Listener Parameter File
/oracle/oracle/product/10.2.0/db_1//network/admin/listener.ora
Old Parameter File
/oracle/oracle/product/10.2.0/db_1//network/admin/listener.bak
The command completed successfully

LSNRCTL>exit