Email Security

Comprehensive behavioral protection

Email Security Software and Hardware Threats eliminated with a layered, behavioral technology approach.

Sendio’s email security technology combines a set of tightly integrated layers that eliminate malicious threats and spam campaigns. We also empower each user in your organization to optimally manage his or her inbox via our unique email community paradigm.

The primary security layers that Sendio applies (in order) to an inbound email are:

  1. Sendio Server Recon – An effective SMTP defense technique developed by Sendio that defeats common spammer automation behaviors
  2. IP Address Reputation – Pattern matching technology to identify malicious senders and their source IP addresses
  3. Anti-Spoofing Technology – Protects your organization from identity theft and other phishing schemes that attempt to steal personal or corporate information such as on-line banking logins.
  4. Anti-Virus – Constantly updated virus signatures for both email body and attachments
  5. Sendio’s Email Community – Using techniques similar to modern social networks, Sendio self-manages a community of permitted email senders for each user in your organization. No more annoying Junk emails or malicious spam, and no more false positives.

Sendio’s email security layers do not employ any content filtering, scoring or statistical techniques in order to stop spam, which allows us to make this promise:

If someone in your community sends you an email, you get it…ALWAYS. You will never miss an important client email again.

Here is more detailed information about each of our security layers for “the techies”:

Sendio Server Recon

Server Recon is a simple and effective technique developed by Sendio to stop automated spamming computer programs. It works efficiently in the background and operates in a completely independent manner relative to our IP Address Reputation technology. This results in very broad real-time email security coverage. Here is how we do it:

Sendio tracks source IP addresses for all email senders to our customers 24 hours per day. When an IP address first sends email to one of our customers, Sendio will defer the email automatically in the SMTP transaction, and then upon retry (usually a few minutes later) the sender’s message is accepted for further processing by the additional email security layers within Sendio. Once Server Recon’s “handshake” is successful, the sender IP address will not undergo the Server Recon deferral again for the next 30 days. Server Recon is fully configurable by each Sendio customer, and if desired specific senders can be exempted from Server Recon completely.

In a nutshell, the vast majority of spammers are defeated by Server Recon without Sendio ever accepting their email as automated spamming systems rarely “retry” a deferred message. Good senders’ email still gets through after a an initial Server Recon event because the whole process follows SMTP email standards and conventions.

The benefits of Sendio Server Recon to your organization:

Brand new attacks for which no security “signatures” exist yet will never enter your network, and your users are kept safe.

Bandwidth is saved because the full emails from many spammers are never accepted.

IP Address Reputation

Sendio’s IP address reputation engine provides protection from spam, viruses, malware, phishing, and other email-borne threats. The engine’s information repository of confirmed bad email senders (based on their source IP address) is updated in real-time 24 hours per day. Sophisticated email pattern detection technology running across the Internet feeds the Sendio real-time reputation engine. Pattern detection includes both recipients of messages and the structure of the messages themselves. This technology is also highly effective against zombie/botnet attacks where clusters of computers and IP addresses work in unison.

The benefit of Sendio IP address reputation to your organization:

Your organization can take comfort that the worst Internet email senders will be stopped in a highly accurate and real-time manner.


Spoofing of legitimate email senders such as banks as part of identity theft schemes can result in significant financial loss to an individual or business. Sendio’s anti-spoofing technology keeps you safe. Sendio utilizes both SPF (i.e. Sender Policy Framework , see for general information) and DKIM signature checking (i.e. DomainKeys Identified Mail, see for general information) within its email processing engine. IT Administrators have full control within Sendio’s web interface on how to apply the results of SPF and DKIM checks to their organization’s overall inbound email policy. As an example, for the SPF feature an Administrator has separate control options for both a SPF “soft” failure scenario (~all in the sending domain’s SPF record) and a hard failure scenario (-ALL in the sending domain’s SPF record).

The benefit of Sendio Anti-Spoofing to you organization:

Simply put, identity theft and other phishing schemes that attempt to steal personal or corporate information are eliminated.


Sendio has you covered for email-borne viruses. Virus signatures are updated in real-time 24-hours per day for both email body and attachment, and the email pattern detection technology within our IP Address Reputation feature stops many new virus outbreaks that don’t yet have virus signatures in place.

Sendio Self-Managing Email Community

For an inbound email where the sending email address is not yet a member of your community, the sender will be invited to join the community via a simple auto-reply email that Sendio calls an SAV (Sender Address Verification) message. The sender simply replies to your SAV message and is part of your email community thereafter and there original message and all future messages are delivered.

If a sender is already a member of your community, then they bypass the verification step.

If you send an outbound email through Sendio to a friend our business associate, that recipient’s email address will automatically be added to your email community and any future inbound emails from that email address require no further verification.

The Benefits of the Sendio Email Community:

This last layer of security provides benefits for both spam prevention and user efficiency. Even if a spammer defeats all other Sendio security layers, the probability is effectively zero that the spammer will respond to the SAV auto-reply because their automation is focused on sending spam not respond to the SAV invitation. User efficiency is greatly increased because annoying Bulk email is eliminated. Each user in your organization can train their inbox via the Sendio interface to only receive the most important bulk emails. All others are stored in Sendio for up to 28 days.”

To learn more, read our Sales FAQ.

We had to deal with spam without blocking legitimate e-mail. For example, we were concerned that filters would not be able to differentiate between fake “Viagra” e-mail and valid e-mail with “Viagra” in the subject. Sendio gave us back our e-mail.
Central DuPage Hospital