A firewall protects your computer or a local area network( LAN )from external intrusions. It may be a hardware device or a software program running on a secure host computer. In either case, it must have at least two network interfaces, one for the network it is intended to protect, and one for the network it is exposed to. More than one type of firewall can be used to provide extra network security. A firewall can also screen internal traffic on a network, separating different departments or branches of a large company. In some cases, a business will configure a proxy server to block employee access to certain types of Internet content, such as streaming audio or video.
A firewall examines all traffic routed between the two networks to see if it meets certain criteria. If it does, it is routed between the networks, otherwise it is stopped. A firewall filters both inbound and outbound traffic. It can also manage public access to private networked resources such as host applications. It can be used to log all attempts to enter the private network and trigger alarms when hostile or unauthorized entry is attempted.
Firewalls can filter packets based on their source and destination addresses and port numbers. This is known as address filtering. Firewalls can also filter specific types of network traffic. This is also known as protocol filtering because the decision to forward or reject traffic is dependent upon the protocol used, for example HTTP, ftp or telnet. Firewalls can also filter traffic by packet attribute or state. If your home or business computer uses DSL, a cable modem, or some other type of always-on Internet connection, a firewall is extremely important.
There are two access denial methodologies used by firewalls. A firewall may allow all traffic through unless it meets certain criteria, or it may deny all traffic unless it meets certain criteria . The type of criteria used to determine whether traffic should be allowed through varies from one type of firewall to another. Firewalls may be concerned with the type of traffic, or with source or destination addresses and ports. They may also use complex rule bases that analyse the application data to determine if the traffic should be allowed through. How a firewall determines what traffic to let through depends on which network layer it operates at.
A Masters student in computer applications interested in writing articles, editing and proof reading Contact at: leenavijayakumar@gmail.com
Friday, February 22, 2008
The Internets Most Popular Email Scams
Phishing Scams:
"Phishing" is a high-tech scam that uses spam or pop-up messages to deceive you into disclosing your credit card numbers, bank account information, Social Security number, passwords, or any other kind of confidential personal information. Identity theft is the goal of this scam.
The phisher sends you a fraudulent email that is designed to look like it was sent from a reputable company. The email directs you to a website that looks like it belongs to the reputable company, but is actually a spoof. You are asked to "update" your information here, and if you do, all that personal information goes straight to the phisher. uses this information for identity theft purposes such as making withdrawals from your bank and credit card accounts, ordering new credit cards which they promptly max out, etc.
Some of the most recent phishing attacks have spoofed the email and websites of well known companies, including eBa, Paypal, Yahoo, Pfizer, Bank of America, among others.
Work-At-Home Scams:
These are some of the more tempting spam scams. They offer those who need to make extra money the opportunity to do so, and invariably the email will state: "no experience necessary." The scammer often claims to have "inside information," and tries to bait you with the lure of quick money for next to no effort. More often than not, you are asked to pay anywhere from $35 to several hundred dollars to purchase the kits or materials that will not earn you a dime.
This scam often offers opportunities involving handicrafts, stuffing envelopes or medical billing on your home PC. If you fall for this scam, pay the fees for the handicraft or envelop-stuffing "kit," and complete the assembly of the crafts as instructed, you will be informed that your work is of poor quality and not worth paying for.
If you sign up for the medical billing "opportunity," you will be asked to purchase a list of doctors. These doctors are either fictional or do not want or need your services and never did.
Credit Repair Scams:
These scams tell promise to erase real and usually correct negative information that has been added to you credit report, so that you can qualify for loans, mortgages, unsecured credit cards, etc.
These services rarely deliver on their promise, and more often than not, will create a great many more problems in the long run. They have even been know to suggest that you commit fraud e.g. falsifying your social security number.
Guaranteed loans on easy terms:
Some email scams offer guaranteed, unsecured credit, such as a home-equity loans that does not require equity in your home, or credit cards regardless of your credit history.
This offer of credit is often extended by an off-shore bank.
This scam is often executed in conjunction with a pyramid scheme, which will encourage you to make earn money by signing up friends and family to participate in the scheme.
The promised offer of a home equity loans turns out to be a useless list of
lenders who will turn you down if you don't meet their qualifications. The promised credit cards never come through, and the pyramid money-making schemes invariably collapse.
Chain letters:
The spam email directs you to send a small amount of money to each of 4 or 5 names on a list, add your name to the top of the list and remove the last name on it, and then forward the updated list via bulk mail. Typically, the letter will claim the scheme is legal, and may refer to sections of US law as supporting proof of this. Not true.
These chain letters are almost always illegal, and nearly all those who participate in them lose their money.
"Phishing" is a high-tech scam that uses spam or pop-up messages to deceive you into disclosing your credit card numbers, bank account information, Social Security number, passwords, or any other kind of confidential personal information. Identity theft is the goal of this scam.
The phisher sends you a fraudulent email that is designed to look like it was sent from a reputable company. The email directs you to a website that looks like it belongs to the reputable company, but is actually a spoof. You are asked to "update" your information here, and if you do, all that personal information goes straight to the phisher. uses this information for identity theft purposes such as making withdrawals from your bank and credit card accounts, ordering new credit cards which they promptly max out, etc.
Some of the most recent phishing attacks have spoofed the email and websites of well known companies, including eBa, Paypal, Yahoo, Pfizer, Bank of America, among others.
Work-At-Home Scams:
These are some of the more tempting spam scams. They offer those who need to make extra money the opportunity to do so, and invariably the email will state: "no experience necessary." The scammer often claims to have "inside information," and tries to bait you with the lure of quick money for next to no effort. More often than not, you are asked to pay anywhere from $35 to several hundred dollars to purchase the kits or materials that will not earn you a dime.
This scam often offers opportunities involving handicrafts, stuffing envelopes or medical billing on your home PC. If you fall for this scam, pay the fees for the handicraft or envelop-stuffing "kit," and complete the assembly of the crafts as instructed, you will be informed that your work is of poor quality and not worth paying for.
If you sign up for the medical billing "opportunity," you will be asked to purchase a list of doctors. These doctors are either fictional or do not want or need your services and never did.
Credit Repair Scams:
These scams tell promise to erase real and usually correct negative information that has been added to you credit report, so that you can qualify for loans, mortgages, unsecured credit cards, etc.
These services rarely deliver on their promise, and more often than not, will create a great many more problems in the long run. They have even been know to suggest that you commit fraud e.g. falsifying your social security number.
Guaranteed loans on easy terms:
Some email scams offer guaranteed, unsecured credit, such as a home-equity loans that does not require equity in your home, or credit cards regardless of your credit history.
This offer of credit is often extended by an off-shore bank.
This scam is often executed in conjunction with a pyramid scheme, which will encourage you to make earn money by signing up friends and family to participate in the scheme.
The promised offer of a home equity loans turns out to be a useless list of
lenders who will turn you down if you don't meet their qualifications. The promised credit cards never come through, and the pyramid money-making schemes invariably collapse.
Chain letters:
The spam email directs you to send a small amount of money to each of 4 or 5 names on a list, add your name to the top of the list and remove the last name on it, and then forward the updated list via bulk mail. Typically, the letter will claim the scheme is legal, and may refer to sections of US law as supporting proof of this. Not true.
These chain letters are almost always illegal, and nearly all those who participate in them lose their money.
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