In the field of email marketing, having a reliable spam blacklist filter is really important to protect your business as well as to have security on all incoming emails. No one knows when and what threats will come, but as to keep your business safety you need this kind of service. To give you a brief idea what is an email spam blacklist filter, it is a piece of program that is installed in mail servers and scan incoming emails and match it on its database for spam security. If the email has found as spam it will not go to your inbox rather to spam folder.

There are different types of spam blacklist like Bayesian filter where you can only select which messages seems spam to you, another is a permission filter where in only authorized emails will be receive by your email, next is rules-based filter which is user defined to block emails. There is also header filter that checks the header thoroughly to identify if it is a spam or not, other uses content filters which is proven to be powerful but sometimes it will give you a problem in newsletters and articles that are sent because most of the time they are caught with this mechanism. If you are familiar with security captcha codes then you can relate with the challenge-response filter, users just need to enter the code displayed as an image in to the text box for as to determined if you are a real human and not a bot.