Spam filter’s objective is to clear your inbox from unwanted messages. This is primarily done by analyzing the received email and marking it as spam or legitimate. The analysis varies depending on the type of filter used – content-based filter, whitelist-blacklist filter, etc. Though spam filters vary in detecting spam, the important features are quite the same and true to all spam filters.
The primary feature of a spam filter is its capability to detect spam. Once a new message prompts, the filter gets alert and automatically checks if it is suspicious in nature. The checking could be based in the content, subject line, HTML code of the message, or the blacklist and whitelist embedded on the spam filter by the user. If the message is confirmed as spam it will be placed in a junk folder or deleted instantly, depending on the chosen option.
In addition, spam filters use point system. Messages coming from unknown senders are given corresponding points. This means that the higher the points the more ‘spammy’ the message is. This message is either blocked or deleted automatically depending on the scale given by the user, say 5 ‘spammy’ words or symbols in a message will cause it to be blocked (delivered in the junk folder) and 10 ‘spammy’ words or symbols will cause it to be deleted. But remember not all blocked emails are spam, some are legitimate.
If your IP or email address is included in the blacklist, your emails will not be received unless you apply for whitelisting. Another feature of a spam filter is its ability to update blacklist and whitelist. If the address is not found in either the blacklist or the whitelist, the filter checks the message. Whenever the message is confirmed as spam, the email address on which that message came from is added to the blacklist. But if the message is accepted due to further actions done by the sender, to confirm his intention, the address is added to the whitelist database.
A lot of emails contain attachments where in some cases, unlikely graphics, pictures and messages are embedded. Spam filter can also check not only the message but as well as the files attached on it.
Now that you know what a spam filter is, its features and the ease it can give, you can purchase one to maintain a clean inbox. But if your problem is about ensuring email deliverability of your legitimate message, promotional or updates, then try visiting http://www.emailreach.com/