MailChannels Outbound Anti-spam

MailChannels Outbound Anti-spam is carrier-grade software that transparently blocks the delivery of spam and malware from your network to the Internet. It is designed to make abuse management easier for service providers and large enterprises.

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Getting Started

Contact us to request a demo. You can install MailChannels Outbound Anti-spam within an hour.

MailChannels Outbound Anti-spam allows you to intercept and automatically apply acceptable usage policies (AUPs) to outgoing email traffic. It lets you centrally analyze and log all email delivery attempts from thousands of servers or millions of subscribers.

MailChannels Outbound Anti-spam also detects and takes action on compromised accounts and scripts so that only clean mail is sent to the Internet. MailChannels Outbound Anti-spam helps you defend your IP address reputation and eliminate email delivery problems.

Designed for:

  • Cloud Service Providers
  • VPS Hosting Providers
  • Dedicated Hosting Providers
  • Internet Service Providers


MailChannels Outbound Anti-spam lets you do almost anything with your outbound email. Combine powerful spam detection, sender behavior tracking, and ultra-scalable software to process billions of messages per month in a single server.

  • Transparently inspect SMTP traffic from thousands of hosts in a single centralized location in the network. The original source IP and destination IP are (optionally) preserved, allowing for truly transparent operation.
  • The full message sending history of each sender is stored in a power database.
  • Write policy scripts to express any conceivable message handling policy. Policy scripts can take action at any stage of the SMTP command and response pipeline.
  • Use ResponseAnalytics™ to understand the error messages given by receiving systems. Know when an IP is blacklisted, and take appropriate action.
  • Send automated notifications to system administrators and abuse team members.
  • Search through terabytes of message delivery logs in seconds using an intuitive web-based search engine.
  • Integrate with external systems using asynchronous HTTP requests or SQL queries. Use a rich set of APIs to automate nearly all functions of the system.
  • All configuration and sender history is stored in a real-time replicated, distributed database.
  • Use PROXY protocol to transparently connect MailChannels instances to load balancers or to tunnel SMTP traffic across the net to distant egress points.
  • Apply traffic shaping techniques to thwart botnet traffic.
  • Transparently capture and redirect SMTP traffic in real-time to sinkholes.

How It Works

MailChannels Outbound Anti-spam presents a comprehensive outbound spam filtering solution, allowing you to analyze email from all your servers and users, identify compromised accounts and scripts, automate common abuse tasks, and implement sophisticated policies in a centralized way.

To use MailChannels Outbound Anti-spam:
  • Contact us to request a demo.
  • Provision a Linux virtual machine or dedicated box (see System Requirements)
  • Configure your routers for Policy Based Routing.
  • Set up initial email policies.
  • Start filtering.
  • Pay only for the amount of traffic you process.

Protect your IP reputation to prevent listings on Spamhaus, SpamCop, Composite Blocklist (CBL), UCEPROTECT, SenderBase, and others.

Software Highlights

Transparent Filtering

Use MailChannels Outbound Anti-spam to analyze all outgoing SMTP traffic from your customer base without configuration changes. You can filter mail coming from servers, subscribers, scripts, and devices and achieve a blacklist-free network.

Compromised Account Detection

With MailChannels Outbound Anti-spam, you can identify and shut down hacked user accounts and scripts in seconds before they damage your IP address reputation and cause blacklisting or delivery problems for all of your users.

Build Reputation

You can use MailChannels Outbound Anti-spam to build a solid reputation and avoid deliverability problems. Use intelligent IP address allocation, apply rate limits, and monitor delivery rates.

Scalability and Clustering

MailChannels Outbound Anti-spam is a carrier-grade solution for processing mail for up to 10,000 servers or 10 million end users on one server. Real-time peer-to-peer clustering means no single points of failure. Take down machines at anytime without delaying a single message.


You can use MailChannels Console to gain visibility into your mail stream. Powerful log search reduces the time required to diagnose delivery problems so you can rapidly build evidence to shut down abusive users.

Internet Service Providers

For ISP Networks, MailChannels Outbound Anti-spam integrates with RADIUS to track users as they move between IP addresses. Rate limits and other abuse management policies follow users from IP to IP without skipping a beat.

Use Cases

Filter Mail Traffic Coming Out Of Your VPS and Dedicated Nodes

Transparent Filtering works in conjunction with your routers. The routers are configured using Policy Based Routing (PBR) to redirect outgoing port 25 traffic from the network to the MailChannels server. With MailChannels Outbound Anti-spam, you can intercept the outgoing SMTP connections, analyze them, and forward them to the intended destination without modifying the source IP address. The mail will appear to be coming from each individual VPS or dedicated server, and your customers don’t know that their mail is being filtered.

Prevent IP Address Blacklisting

Like a credit card, if you don’t make payments on time, the credit bureau gives you a bad credit score. Similarly, email reputation is influenced by how recipient networks interpret your mail traffic. Each time you send spam or try to deliver to a non-existent user, a database records this against your IP address. Over time, bad behavior gives your mail server a bad reputation, which may cause you to be added to global real-time black lists (RBLs).

You can use MailChannels Outbound Anti-spam to streamline, automate and manage the abuse of email accounts and mail servers as spammers so that your team spends more time growing the business instead of reacting to fraud.

Detect Spamming Behaviour

Credit card companies monitor for suspicious activity by flagging several different kinds of behaviors that don’t fit a cardholder’s profile. You can use MailChannels Outbound Anti-spam to monitor each customer account for suspicious activity in a similar way because spammers behave differently than legitimate users. Receive alerts the moment a user, script, or server starts spamming.


MailChannels Outbound Anti-spam relieves service providers of the cost and complexity of managing email abuse and IP reputation.

With MailChannels Outbound Anti-spam, you only pay for what you use. You are billed on a monthly basis, and discounts are available for long term commitments.

MailChannels Outbound Anti-spam starts at $500/month for up to 5 million messages per month.

For companies processing more than 5 million messages per month, contact our sales team for pricing and evaluation information.

System Requirements

We recommend using a server with eight processor cores and 32GB of RAM. The following configuration will process at least 30 million messages per hour, with connection bursts greater than 10,000 SMTP connections per second and concurrency handling exceeding one million concurrent SMTP sessions:

  • 8 x 64-bit Intel or AMD CPU cores
  • 32 GB RAM
  • 1 x 1000BASE-T NIC
  • 500 GB SSD disk space

MailChannels Outbound Anti-spam is designed for Linux kernel 2.6.32 and higher, and is certified to work with Ubuntu 12.04 LTS 64-bit, Ubuntu 14.04 LTS 64-bit, and RedHat Enterprise Linux 6. Compatibility with other Linux distributions is not officially supported by MailChannels.

Request a demo Deploy outbound spam filtering within an hour.
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