The overall Heluna system is divided into multiple stages that a message passes through prior to being delivered to your inbox. If a message successfully navigates every stage of filters, it gets placed into a delivery queue, and is sent along to your mail server immediately.
Each stage of filters assigns a score to the incoming message, and based upon the user's filter sensitivity (set in the control panel at the individual or domain level), the cumulative score of the message determines the action that the system takes for that message.
Messages get placed into one of three buckets: "definitely spam", messages that the system has identified as absolutely a spam message, "possibly spam", messages that the system thinks might be spam but isn't absolutely sure, and "clean", messages that the system thinks aren't spam.
The border servers accept messages and perform initial filtering, including reputation filters, DNSBL queries, SPF checking, and recipient validation.
Messages from senders with extremely good reputations are able to bypass further filters and get immediately delivered, while messages from senders with extremely poor reputations get quarantined immediately.
The core filtering servers process the primary message queue, and apply bayesian machine learning, content filtering, URIBL queries, and more.
After a message is processed in the core, we determine the next action for that message based upon the user's preferences. Clean messages move to the delivery system, while spam messages are added to the user's quarantine.
Every message that passes through the Heluna system gets added to a learning queue, which processes and adds to the bayesian network.
Once the message is learned as either clean or spam, the contents of the message are discarded, so there is no record of any clean message content inside Heluna.
Heluna captures a large amount of log data about a message, without saving the contents of the message, and you can see this log data on the dashboard.
The visibility into your mail logs can help you debug issues with your own mail server and see exactly what happened to each message that came into Heluna.
Once a message makes its way to the delivery queue, the deliver cluster picks up the message and attempts delivery to your mail server. If your mail server is offline, we'll automatically retry delivering the message for up to thirty days.
The entire process, from border to core to delivery, takes place within seconds, ensuring that you get efficient, timely email delivery.
Catch senders with bad or unknown reputations online
Block hundreds of thousands of spammers by IP address
Find brand new spam originators sending to invalid addresses
Ensure messages are only allowed to originate from accepted servers
Prevent dictionary attacks on your infrastructure
Machine learning for spam messages, high confidence spam filtering
Catch messages that have spam URLs embedded in them
Filter out messages based on headers or body content
Adjust the score a message needs to get to be quarantined or delivered
View current message logs and statistics for users or domains
Daily or weekly emails with the contents of user or domain quarantines
Senders marked as possibly spam can be overridden and set to clean
Block messages from senders who you never want to see
View or immediately resend a message from your quarantine to your inbox
Preferences, logs, statistics, and quarantine run at the individual mailbox or the domain-wide level. Individual mailboxes inherit the domain preferences if a Heluna login isn't set up for that mailbox.
View statistics, invoices, individual user actions, logins, and more at the account level.
Set up individual logins with distinct roles: either a regular user mailbox, a domain-wide admin to manage a specific domain, or an account admin to manage all domains under your account. Logins can enable two-factor authentication for additional user security.
New clients are encouraged to let the Heluna system run with minimal customization and preferences for a while; if your users are logging into a website to constantly review quarantines, add approved senders, and so on, you aren't reducing the cost of spam at all. Heluna strives to be completely hands-off, and we encourage our users to treat us as an invisible layer of filtering.
Heluna provides opportunistic TLS encryption for all incoming and delivered messages, and only allows TLS/SSL access to the client dashboard. We don't keep any copies of clean messages that have been delivered to your domain. When you use Heluna, you can rest assured that your email is secure.
The Heluna website also uses optional two-factor authentication to secure your account. You can browse your message log, set your preferences, and see your statistics all while knowing that only you can see your information.
We've engineered the overall system architecture to be reactive under load. Using Amazon's AWS, Heluna can scale to meet incoming message demand very efficiently. Even under heavy loads, Heluna provides comprehensive message filtering for all of your email.
With modern architecture and operations setup, the Heluna service is built to be extremely resilient to component failure. Thanks to the nature of SMTP we make sure that you're never losing messages even when your mail server goes offline.