Email Blocking

The vast majority of malicious email attempts to conceal its origin, claiming to be from well known servers, or originating from a temporary internet connection like a dial-up line. We block these attempts using several tools:

Once the origin has been established, we check to see if that origin is a known source of spam, or a known temporary connection. To accomplish this we check the origin against a number of blocking lists.

We also maintain our own blacklist which includes a number of domains which have given us problems in the past, as well as several Top Level Domains which are known as sources of malicious email because of lax laws/enforcement in the countries designated by the TLD.

Email attachments are checked for MIME compliance, and any files with executable attachments will cause the email to be rejected. We then pass the email through the Clam Anti Virus filter, and reject any messages we find with embedded malicious software. Our virus filters are updated hourly.