Start a conversation

Can you provide a summary of each filtering mechanism?

The following provides a summary of MWES's filtering features.


The whitelist includes email addresses from which all emails are accepted, regardless of their content.None of MWES's junk mail filters are applied to messages from addresses on the whitelist, therefore care must be taken when adding addresses.It is possible to avoid false negatives by ensuring that you do not add entire domain names to your whitelist, for example, *


MWES filters all messages from addresses that appear on the Address blacklist.All users are affected by the Address blacklist, therefore it is recommended that entire domains are not added to the blacklist as this prevents all endusers from receiving possible legitimate messages from any address at that domain.

IP-based RBLs

Real-time blackhole lists (RBLs) are used to list the servers and domains of organisations that have been identified as senders of junk emails.IP-based RBLs (ip4r RBLs) are lists of IP addresses of servers that have been identified as sending or relaying junk mail.Firetrust recommends that you carefully investigate each RBL service for accuracy, before you begin using them. Inaccurate RBLs can result in a high false positive rate.

URI-based RBLs

A URI RBL is an RBL that lists the domain names and IP addresses which are found in the "clickable" links contained in the body of spams, but generally not found inside legitimate messages.


FirstAlert! is a database of reported and known junk mail messages that is used to eliminate future circulation of junk mail. FirstAlert! provides real-time spam signature updates.


Greylisting is an effective tool to stop spam by sending a temporary fail back to the sender of the message.If the sender is sent via a valid MTA, the message is re-sent and MWES will let it through. If the message is not sent from a valid MTA it is not delivered and left in the MWES greylisting quarantine area.

NOTE: Valid messages can be delayed by up to 15 minutes using this method since the sending MTA has to re-send the message.You can always check the quarantine>>greylisting area to see which messages are due to be resent, and thus rescue them in which case they will be added to the whitelist.See below, the three light grey messages at the top are within the 15 minute time period to be re-sent. One an email sender has been let through, they are let through instantly next time they send something.

Custom filters

Custom filters can be added using text or regular expressions to block unwanted email based on words and other characteristics of an email.

Bayesian Filtering

Learns from good and spam email based on the administrator initially training it, becomes very accurate after a short while.

Choose files or drag and drop files
Was this article helpful?
  1. NB

  2. Posted