Exchange Server Email Filter

Creating an email filter for an Exchange Server is one of the best steps a group can take in order to prevent unwanted spam, increase security against email-borne threats and ensure email continuity during downtime.

Although Exchange Servers provide a level of email filtering by default, the software provided lacks the key tools to enable the detection of complex spam and malware. An email filter for an Exchange Server resolves this issue with real-time spam detection and strong anti-virus software.

Exchange Server email filters also supply email continuity. This can be critical for a group in the event of downtime during an outage, hardware failure or natural disaster – allowing communication to go on, and preventing loss of business and loss of credibility.

Exchange Server email filters implement multi-layered security mechanisms to assign each inbound email a spam confidence level. Every email is reviewed against a blacklist of IP addresses from which spam email has originated in the past and analyzed for compliance with sender policy frameworks.

If an email exceeds a specified spam confidence rating it is tagged and either sent to the intended recipient tagged as spam, quarantined or deleted. The filter then produces a report of all tagged/quarantined/deleted emails so that genuine emails can be reinstated and their senders added to a whitelist.

An email filter for an Exchange Server also scans outbound emails to review for any content or attachment that could be categorized as spam by a global blacklisting agency. This prevents an organization´s IP address from being included in a blacklist, with a subsequent delay in the delivery of emails sent by the organization until the issue is addressed.

In order to evaluate an email filter for an Exchange Server, you need to start by holding it up against the premium service offered by Microsoft – “Exchange Online Protection” (EOP). EOP replaced the company´s “Forefront Protection for Exchange” when Exchange 2013 was released; but unlike its predecessor, EOP is only available as a cloud-based service.

There are many known problems with EOP that make it a poor substitute for a third party email filter for an Exchange Server. EOP does not have real-time dynamic link following, “sandboxing” and “greylisting” – an essential function to detect spam emails. The premium service has also been criticized for including a high maintenance overhead – smaller organizations preferring usability over complex customization options.

Although all third party Exchange Server email filters provide email continuity, they vary in their ability to stop unwanted spam and increase protection against online threats. Due to this, when evaluating an email filter for an Exchange Server, organizations have multiple considerations to take into account. These include:

  • What are the deployment options?
  • How is the spam detection rate calculated?
  • What anti-virus software is used to identify email dangers?
  • Are there any known compatibility problems?
  • Is the email filter for an Exchange Server scalable?
  • Does the service supplier have knowledgeable and reliable customer support?
  • Can the service provider supply independent reviews?

Depending on the size of your group and the nature of its business you may have more considerations. For example, groups with a restricted IT budget may demand flexible payment options. Larger organizations may want APIs to integrate the email filter with other management tools, while Managed Service Providers may require deployment in a private cloud and a white label option.