How to prevent spam

Source: http://www.wordsandpeople.com/security/how-to-prevent-spam.htm

Spam: If you have an email address I bet you're fed up with the unsolicited mail you receive. The increase in spam has virtually relegated email as an adult only facility. Spam is a waste of our time. Many spam emails are obscene, many are offensive or insulting to one's inteligence e.g. "I have a zillion pounds that I want to put into your bank account, please fax your bank account details to me...This is not a scam, honest!".

There are two sides to preventing spam:

1. Stop them getting your email address: The rest of this page is about how the spammers get your email address and how to stop them from getting it.
2. What to do if they have got your email address. If the spammers have already got your email address I recommend that you change it to a new address - after you have read the rest of this page and taken the appropriate action to stop them getting your new address. If you can't change your email address here is an excellent and free spam filter: Spam Bayes.

Types of spam and ways to prevent it

To stop receiving spam it helps to know what kind of spam you are getting. Each type of spam requires a different method of prevention. Below are the types of spam (I am aware of) and free methods to preventing them.

• Harvested address spam

  What is it: This is probably the most common type of spam. The spammers use a computer system (spider or spam-bot') to check almost every website on the internet (including yours). The 'spam bot' looks at the code of every web page, it looks for the '@' symbol. When it finds an '@' it knows its found an email address. It then collects the bit either side of the '@' symbol to capture your email address and add it to the spammers database of millions of harvested addresses. From then on that address will receive lots of spam!
  
  How to find out if your email address is published on a website: Go to Google.com and type your email address into the search box. Google can usually show if your email address is on any website. If google can find your address you can be sure the spammers have got it. Tip: Sometimes the website-page with your email address may be very long, from Google click the link that says 'Cached' and you will see the page and your email address will be highlighted.
  
  The solution: If the spammers have harvested your email address from a website they are not going to let it go. Get a new email address and make sure your new email address is not published online. If you must publish your email address on a website get your website designer/manager to encrypt your email address so the 'spam bots' can't harvest it as they robotically and relentlessly crawl the web.

• Virus Spam

  What is it? This is perhaps the 2nd most common type of spam.

  1. Somone else's computer (not yours) gets infected with a virus.
  2. The address book on their computer has your email address.
  3. The virus sends a spam to every address on the address book.
  4. The virus 'spoofs' the 'from address' in the email it sends i.e. the spam does not appear to have come from the senders email address, instead it says it came from another address taken from the address book.
  5. There is no point replying to the spam e.g. to say 'don't spam me' or 'your computer has a virus' - as the 'from address' is wrong, which means it will go to someone who didn't send the spam. (note this is why you might receive emails from people saying you sent a virus to them, when you know your computer is clean).
  How to prevent it: You can not prevent virus spam from being sent to you. The person with the infected computer needs to use quality anti virus software to clean their computer (see preventing computer viruses). You need a good spam filter to delete this kind of spam as it arrives.
  

• Domain name spam

  What is it? If you own a domain name for a website you are probably getting domain name spam. Spammers use the whois database to obtain a list of most of the doman names in the world (ie .com, .net. org). The spammers expect most website owners to set up generic email addresses such as sales@... and info@... They simply send spam to all of the standard generic words at email every domain name in the world.
  How to prevent it: Do not have a generic email address such as sales@ and info@. Instead have less usual addresses. Here is a list of all of the generric words (I am currently aware of) the spammers are using:
  - info@
  - mail@
  - sales@
  - contact@
  - contacts@
  - root@
  - home@
  - contacts@
  - enquiries@
  - webmaster@.
  
  Note: do not use 'catch-all forwarding' that forwards anything@ your-domain. Block all but specific names at your domain. Your website designer should be able to help you follow these steps.

• Dictionary spam

  What is it? You can sometimes receive dictionary spam when you use a well known email service. The spammers know that there is going to be a [email protected]. They setup computers to spam billions of names at that mail service simply by targetting every persons name.
  How to prevent it: Hopefully your email service provider has put anti spam systems in place to prevent this kind of spam. If they havn't then you may have to find a better email servide provider.
  

• Windows Messenger Spam

   

  Do you get pop up boxes on your screen with the words "Messenger Service" in the title bar? If so you may be getting Windows Messenger Spam. Follow this link to learn how to turn off Windows Messenger Service.

• Hacked mail service spam

  Some ISPs or webmail services may be hacked by spammers or the addresses may be sold to spammers. Read the small print when signing up for an email account. Look hard for that box that says 'we might give your address to a 3rd party, tick here if you do not want to recieve marketing info from other companies...'.
  If you can't change your email address here is an excellent and free spam filter: Spam Bayes.

Hoax Spam

These are messages that innocent people may forward to you with some kind of hoax warning or way to make a fortune. Never respond to or forward this kind of message. They are hoaxes, see real example below. If you 'CC' (copy in) your friends and contacts you may be providing a way for spammers to harvest the email addresses of your friends/contacts. These rubbish emails sometimes end with something like: "Try it; What have you got to lose?"
What you have to lose is your privacy and credibility!

Typical example:
PLEEEEEEEEASEREAD!!!! IT WAS ON THE NEWS!!
Dear Friends, Please do not take this for a junk letter.
Bill Gates is sharing his fortune. If you ignore this you will repent later. Microsoft and AOL are now the largest Internet companies and in an effort to make sure that Internet Explorer remains the most widely used program, Microsoft and AOL are running an e-mail beta test. When you forward this e-mail to friends, Microsoft can and will track it (if you are a Microsoft Windows user) for a two week time period. For every person that you forward this e-mail to, Microsoft will pay you $245.00, for every person that you sent it to that forwards it on, Microsoft will pay you $243.00 and for every third person that receives it, you will be paid $241.00. Within two weeks, Microsoft will contact you for your address and then send you a cheque. I thought this was a scam myself, but two weeks after receiving this e-mail and forwarding it on, Microsoft contacted me for my address and within days, I received a cheque for US$24,800.00. You need to respond before the beta testing is over. If anyone can afford this Bill Gates is the man. It's all marketing expense to him. Please forward this to as many people as possible. Try it; What have you got to lose????

More tools and tips to prevent spam

• Anti spam software: There are many tools you can use that check incomming mail and try to detect which is spam and which is not. The spam emails are sent to a 'trash' folder on your pc. This is the spam filter I recommend and its free: Spam Bayes.
• MailWasher.net is a free tool to check and manage your e-mails before you download them. I used to use this tool when I received a lot of spam. Its easy to use and free. The main benefit is that you can reveiew your email before downloading it, and delete the spam remotely.
• Avoid CC (carbon copy) for group emails that you send out.
  If you send an email (to a group of people) that might be forwarded on and on, it could get into the hands of a Spammer, who you can be sure will add the nice collection addresses to their spam address database. Instead use BCC (blind carbon copy), this means the recipients do not see the list of email addresses that your message has gone to. Also encourage others to use BCC for groups instead of CC.
• Never add your friends email address to a mailing list.
  You will not get a free prize and your friend will not thank you for the extra spam they receive.

Why doesn't my anti-spam software prevent all of the spam?

Much anti-spam software identifies spam by the following methods:

• Blocking email from known spammer addresses.
• Identifying obscene words in the email.
• Identifying a form e.g. 'click here to buy this rubbish'.
• Identifying certain sales/marketing words.

Many spammers use systems to do things like the following

• Each individual spam email of the millions they send appears to come from a different address.
• The invite to buy something is actually an image of text not real text so it can't be read by your computer. The text behind the image is random words that you don't see but look innocent to your computer.
• The invite is to click a link for a website, so there is not a form on the email. The form to buy something is on the website.