Email Relay and Spam Filtering Service

As part of our investment in resources for our customers, CNS has built a bespoke spam filtering system which can be tailored for the individual needs of each business. This system is housed in our partner datacentre, with multiple servers and dual dark-fibre links for redundancy, giving enhanced security and system availability. We believe that this is the best spam filtering system available and that our Premium customers will greatly benefit from its use.


End-to-end security is vital for your email, so from the moment your email message arrives at our datacentre, it is encrypted and remains so during every transmission of the message. Each email is checked and cleaned of any viruses or spyware using state-of-the art scanning systems, and once the email has been put through our rigorous spam filtering system, it is delivered to your email system in an encrypted form.


Whitelisting is in effect the opposite of blacklisting. If a domain appears on a World Whitelist, it means it does not require regular checking by security programs, which speeds up processing and ensures your messages are not held up.

Part of our spam filtering service is the inclusion of your domain in our White-listing program – we invest many hours in adding email domains to World Whitelists, implementing spam score-reduction techniques and whitelisting all the email servers involved, to ensure that any email you send always arrives.

Failover & Reliability

If the internet connection to your office is unavailable for some reason (maybe having become disconnected or unstable), under normal circumstances any incoming emails would be bounced back to the sender, or simply dropped. Because our servers are the first port of call for your emails, our spam filter will automatically hold them for you on our server until your normal service has been resumed, and then deliver them as normal, bringing to an end the mystery of disappearing emails.

Custom Controls

Our Spam Filter Portal has been custom made for people who receive a lot of spam, hold multiple email addresses, or simply like instant updates. Users can monitor their individual email and configure custom white & black lists, delete spam and instantly release clean emails with a couple of clicks – ultimate security and convenience.

If you’d like to talk to us about our Email Relay and Spam Filtering, get in touch