antispam software

There are different kinds of filters:

User defined filters are included in most email clients today. With these filters you can forward

email to different mailboxes depending on headers or contents. For example, you would put email

from each of your friends into a mailbox named after them. You can also use these same filters to

forward email to the trash if the origin or contents are suspicious. To do this you need to

carefully look at any Spam emails you receive. Try to notice common characteristics, recurring

patterns in senders’ email addresses, dubious claims in the subject line and so on. You will soon

find that Spam filtering using a small number of rules can eliminate a large number of Spam

emails.

Header filters are more sophisticated. They look at the email headers to see if they are forged.

Email headers contain information in addition to the recipient, sender and subject fields

displayed on your screen. They also contain information regarding the servers that were used in

delivering your email (the relay chain). Many spammers do not want to be traced. They put false

information in the email headers to prevent people from contacting them directly. Some anti spam

programs can detect forged headers which are a sure indication that the email is Spam. Not all

Spam has forged headers though, so this filter by itself is not sufficient.

Language filters simply filter out any email that is not in your native tongue. It only filters

out foreign language Spam, which is not a major problem today, unless the foreign language under

question is English. In future, languages other than English are expected to make up an

increasingly large percentage of Internet communications. If you do not expect to get emails in

another language, this may be a quick and easy way to eliminate some portion of your Spam.

Content filters scan the text of an email and use fuzzy logic to give a weighted opinion as to

whether the email is Spam. They can be highly effective, but can also occasionally filter out

newsletters and other bulk email that may appear to be Spam. This can usually be overridden by

explicitly authorizing email from domains you subscribe to.

Permission filters block all email that does not come from an authorized source. Typically the

first time you send an email to a person using a permission filter you will receive an

auto-response inviting you to visit a web page and enter some information. Your email then becomes

authorized and any future emails you send will be accepted. This is not suitable for all users,

but very effective for those that choose to use it, as long as the auto-response email is not

blocked by the Spam filter of the initial sender!