Raggedstaff Internet
Keeping your inbox clean
 

Mail filters



Keeping spam and viruses out

Raggedstaff provide advanced email filtering to help keep your inbox free of unwanted junk and viruses. There are two different types of filter available, each complementing the other to provide effective protection for you inbox. All filtering options can be configured on a per recipient basis.

Envelope filters

Envelope filters, sometimes called handshake or protocol level filters, are applied during the initial connection from a remote server trying to deliver mail, before the actual mail even reaches Raggedstaff's servers.

We run a series of tests on the incoming connection, such as the nature of EHLO argument used, whether the remote server has a valid reverse DNS entry and whether it is listed in a DNS based block list, and assign a score for each test failed. If the score exceeds a set threshold the message is rejected.

The tests run, the scores assigned and the threshold for rejecting are all under your control and can be configured seperately for each recipient in your domain.

By assigning weighted scores to each test we are able to achieve a much lower false positive rate (legitimate mail being rejected) than with the more conventional method of rejecting anything that fails any test.

Content filters

Content filters are tests done on the content of a message (including its headers) after the message has been received. Our content filters check for two main types of problem:

Virus filters

Mail can be checked for viruses using virus scanning software that is regularly updated (usually several times a day) to ensure that the latest threats are detected. Infected mail can be rejected or passed on to you as an attachment to a short message warning that the attached mail is infected.

Spam filters

Spam checking is carried out using SpamAssassin technology to analyse the contents of messages and assess the liklihood of a message being Spam. Spam can be flagged, either by adding a tag to the message subject or using a special message header, to allow you to filter it out with your email programme.