• If you have been using the Internet for a long time, you have probably already received a large number of unwanted emails (Unsolicited Bulk Email). Some claim to make you rich quickly. The rest promise new products or services. Some occupy a space in your mailbox and ask you to send the email to others or visit a specific website. In the online community, unwanted e-mails (sometimes commercial) are called spam. Spam is more than a nuisance to Internet users and seriously affects the efficiency of the network and email servers. This is because it costs spammers very little to send hundreds of thousands or even millions of emails at once. Spam attacks take a lot of bandwidth, fill in mailboxes, and waste e-mail readers’ time. Sometimes you can recognize spam by their strange, irrational, and ridiculous subject lines. The table below shows the percentage of emails that have been recognized as spam over a one-year period broken down by month.
  

  	Percentage of all emails known as spam
  March 2004	63%
  February 2004	62%
  January 2004	60%
  December 2003	58%
  November 2003	56%
  October 2003	52%
  September 2003	54%
  August 2003	50%
  July 2003	50%
  June 2003	49%
  May 2003	48%
  April 2003	46%

  As stated in the table, in the first months of 2004, nearly 63% of all sent emails were spam. This number reached 83% in 2005. Other statistics show that spam emails are 10 times smaller than ordinary emails in size; however, in 2005, every day 2.5 TB of spam was sent, which is astounding in its own right.

  Imagine there are only 15,000 Internet users, and each one gets 50 spam emails every day. Now we assume that scanning and deleting every spam takes only 2 seconds. This means just wiping off the spam takes users more than 2,500 hours per week. However, the actual figures were higher than the above example and are growing every day.Now, it’s clear how these unwanted emails affect the productivity and effectiveness of Internet users.

  In addition, another important point about spam is its inappropriate content. Spam is sometimes used to spread viruses, Trojans, and spyware.

• SMTP: The Internet uses the Simple Mail Transfer Protocol (SMTP) to send email messages. This protocol was designed many years ago, when the Internet was a much smaller and friendlier network than the current one, which is why it is weak in terms of security. One of the main weaknesses of this protocol is that it’s easy to hide the sender’s identity.
• Open Relays: This term refers to Mail Servers, which allow Spammers to send spam through these servers and hide their identities due to weaknesses in the design or configuration of the Mail Server.
• Bot: Bot is an abbreviation for Robot. This term refers to a computer that is used to send spam (Relay). A computer is converted to Bot when it is infected by a Virus, Trojan Worm or Trojan Horse which are designed to install Backdoor on the system. Backdoor is a program that allows spammers to have access to and control the system, and then spammers use the system to send spam. One of the most common and effective methods spammers use to send spam is first they infect the computers of a great number of internet users by spreading Virus and Spyware on the Internet, and then, in their own methods, detect and control infected computers. Thus, they start spamming from computers in many parts of the world (most of them personal computers connected to the Internet via DSL lines). This is how every day a huge amount of spam is being sent from PCs in to the Internet world. It’s clear that great volume of spam can be reduced through applying several simple policies and managing emails sent from personal computers.
  If the volume of emails sent from PCs that are connected to the Internet is not controlled, serious risks will threaten internet users and service providers.Personal computers connected to the Internet that are controlled by spammers or unauthorized persons are called zombies or botnets.
  Every day, more than 80% of the spam is sent by Zombies.

• Do not give your email address to others with no reason:
  Email addresses have become so common that you can notice a specific field for your email address on all forms that collect your personal information. A large number of people record their email address everywhere and in all forms without considering the potential risks.
• Examine Confidentiality Policies:
  Always ask yourself if you are recording your email address on sites that are trustable or not. You must, before sending your email address or other personal information, read the policies announced by the site, and find out what the owners and / or site authorities are about to do with the information you provide them with.
• Be careful with the options that are enabled by default:
  When you “Sign In” for a new service or account, there may be a part that will provide you with a set of options for receiving emails on new products or services. In some cases, options are selected by default. So if you leave them in the situation as they are, in future, you will receive a great number of electronic mails that you may not expect.

A large number of mail programs have the ability to filter. This will allow you to block certain addresses or to receive mail only from the contact list on your computer.

Never click on the links in Spam Emails:
Some spam sources attempt to authenticate an email address by sending a variable of email addresses in a particular Domain. (For example, identifying valid email addresses on Hotmail or Yahoo). If you click on a link sent by a SpamEmail, unwanted messages including the tempting “unsubscribe” link, you are in fact letting them use this tool to ensure that your email address is valid. (By clicking on these links, you will ensure the Spammer that in addition to receiving the spam email, you have read the content!)

Disable automatic download of graphics in HTML formatted emails:
A large number of companies send HTML formatted emails with a graphic link, which is used to track the person who has opened the electronic message. When your email client application downloads a graphic file from the server, they will know that you have opened the electronic message. By disabling HTML Mail and viewing messages in plain text format, you can avoid this.

Creating additional new accounts:
A large number of sites are offering email addresses for free. If you are constantly using email (for online shopping, receiving service, etc.), you may have to create another account in order to protect your primary account against spam. Additionally, you must use another account when you send information on to online news bulletins, chat rooms, public mailing lists or Usenet. Thus, you can create an appropriate level of protection against receiving spam on your primary email address.

Do not send spam to others:
Be a committed and responsible user. Act rigorously about messages that you intend to forward. Never forward a message to all contacts in your address book, and if someone asks you not to forward a message to them, respect them and their request.