There are several ways to block spam, none are 100% effective,
but 95% is a reasonable expectation. To increase spam filters'
effectiveness, remember to 'train' yours by marking incorrectly flagged
messages rather than simply deleting them. The following mechanisms are
available to combat spam:
Most e-mail storage server providers (often the same as
your Internet service provider) offer a spam blocking service. Some
charge extra to use this, others bundle the cost in with the service.
Typically your e-mail may have the subject prepended with a fixed string such
as [-SPAM-] when it thinks the mail is junk. You can then set up most e-mail
clients to filter such mails to a special mailbox.
Your anti-virus product - or more accurately, your Internet
Security package, may have a spam filter built in.
You can run a program to do this. As is often the case, you
can get free ones, or you can pay for better quality. Some examples of
well reviewed products that I have no experience of are:
Most mail clients e.g.
(part of the Office suite), Eudora, &
Thunderbird can do
this. Outlook Express (freely bundled in with Windows) can not.
It is possible to set up a free webmail account (e.g.
that traps spam then configure your e-mail client to collect from the webmail account using
POP. Your own e-mail address may need to be personalised for this to
If you have your own domain name (e.g. email@example.com)
your registration agent may provide you with the ability to
This is a development of the previously favoured whitelisting (where your
correspondents have to opt in to allow their message to be received by you),
and blacklisting (where incoming mail is checked against a list of known
spammers and rejected if there is a hit). When an e-mail server
receives a message, it initially rejects it with a temporary failure code.
A standard mail server will simply requeue the message to be delivered a few
minutes later. On second presentation the e-mail server accepts the
message as genuine and you receive your message. Many spam
distributors would not bother to investigate failures and so do not resend
the message after the initial rejection.
Policy Framework (SPF)
targets forged senders (as most spam messages contain). It works by
adding extra information to the domain system that says which IP addresses
are allowed to send mail for a particular domain.