I’ve been a fan of Sendio email security technology for many years.

The appliance is a rock-solid email processing server that scans all outbound messages for addressees to add to the accept list and scans against nasty viruses we may inadvertently try to bombard the world with. The appliance performs simple processing on inbound emails as well, which can include, if administrator so chooses, scanning for viruses, attachment policy compliance (no .exe please), sender comparison to an accept list, and even send a challenge-response message to the sender confirming that I have not yet received the email and requesting confirmation from the source in order to deliver it. Administrator can turn these features on and off for specific accounts too.

Even before the Sendio ESP accepts the message, it applies ‘graylisting’ where the server determines whether or not the sending IP address has ever communicated with the appliance before. If not, the ESP presents a standard ‘I’m busy, try again’ message in which well-behaved email servers try again in a few moments while spambots move on.

Two weeks ago, we rolled out the latest release of Sendio ESP 5.0 on our server. The upgrade went seamlessly and returned to service without disruption. Significantly, the daily queuing option, allows users to see the messages being held in the queue (received pending confirmation from senders). In the previous release, users were presented with three practical options:

• the option to accept the message (A-MSG) which would pass only that message to the user’s email account.
• accept the sender in (A-SND) which case all messages from that sender would be released.
• do nothing which kept the message in the holding queue.