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SentiLAN™ - E-mail Monitoring


quote E-mail has gone from novelty to probably the most business-critical communication medium of the decade.

Being without it just isn't an option. quote

E-mail has, without a doubt, become one of the most critical forms of business communication. However, it can also be notoriously unreliable with no guarantee of message delivery, nor the time taken for message delivery.

Many of today's e-mail implementations will be highly complex, comprising anything from one to hundreds of internal e-mail servers. On top of that will be a number of different security and anti-virus packages. Outside the network, there may be third-parties doing e-mail scanning for viruses, spam, phishing and other malware.

This results in an infrastructure where an e-mail message has to pass through many hops in order to reach its destination. Any one of these hops could be non-functional, or performing below normal levels.


Many e-mail monitoring solutions merely check that the public facing interface is willing to accept connections. Unfortunately this is just the tip of the iceberg in terms of what goes on beyond that initial connection. If a third-party is used to do an initial scan of the messages for malware/spam, then it is not even the internal system that is being checked.

The only reliable way to determine an e-mail system is working is to send and receive messages through it - all the way from one end to the other.

SentiLAN Monitoring

Exmos' SentiLAN system performs a full end-to-end e-mail monitoring process.

There is an e-mail loop in operation, sending messages both into and out from the core e-mail servers (e.g. Exchange Server). These messages take the exact same route as if they had been sent by a person. SentiLAN sits in the middle of this loop. It controls the sending and monitoring of the message flows.

Each message sent into the e-mail system is processed internally (by a very small agent application) and sent back to SentiLAN. At the same time, a completely independent e-mail is sent from inside the network to SentiLAN. It can then identify where perhaps inbound messages are not being received, but outbound e-mail is still functioning correctly.

Email Monitoring - Roundtrip of messages diagram

Importantly, there is no requirement to install any complex software on the e-mail servers.

Depending on the level of service purchased, this check is carried out anything from every few hours down to every few minutes (depending on how critical the customer classes their e-mail service).

SentiLAN e-mail monitoring currently processes around 3.5m e-mail messages per year.