Outbound Spam Filter

An outbound spam filter is not a mechanism one usually considers when evaluating the options for reducing the volume of spam mail a business receives. However, it is an important feature of advanced spam filtering solutions that can prevent your business´s IP address being blacklisted.

There are several reasons why your business´s IP address could be blacklisted for sending spam emails. A badly spelled email or an email with too many spam-related keywords could be quarantined as spam by an inbound email filter with a low acceptance threshold.

The email sent by your business´s email account could be flagged as spam in error by the recipient and reported by their email service provider to a blacklisting agency – who would then place your business´s IP address on the Realtime Block Lists (RBLs) used by all email filters.

The consequence of your business´s IP address being blacklisted is that none of your suppliers or clients would receive your business emails. They would either be blocked from delivery or quarantined as spam. Being removed from Realtime Block Lists is a time-consuming process and, while you are waiting, you would have to use alternate web-based email services to communicate by email.

An Outbound Spam Filter Prevents Other Potential Issues

There are several – more disturbing – scenarios why your business´s IP address could be blacklisted. It could be the case that somebody is actually using your mail server to send spam emails – either an employee or an outsider who has hacked into your system and stolen a user´s login credentials.

An employee´s use of your email server is likely a serious disciplinary matter. But if an outsider has hacked into your system or has acquired a user´s login credentials, the most serious concern should be what other information might they have acquired and how they are using the account.

In some circumstances, it is possible that your business´s IP address can be been blacklisted for sending malware-infected emails. The infection might not even be in your network. It may have originated from an employee´s infected home computer should they have prepared a file at home and attached it to a business email.

Many advanced spam filtering solutions can check for malware and malicious links within inbound emails and their attachments using “URIBL” and “SURBL” databases. If a malware-infected email was received from your business email account, the recipient´s spam filter – or the intended recipient – could report your business´s IP address to a blacklisting agency.

  • Safeguard your IP reputation.
  • Stop employees sending spam.
  • Prevent the spread of malware.
  • Identify compromised accounts.

SpamTitan’s Advanced Spam Filtering Solutions

SpamTitan Gateway and SpamTitan Cloud are TitanHQ’s advanced spam filtering solutions. Both include an outbound spam filter that prevents all of the above scenarios by scanning your business´s outbound email for those that could be classified as spam or those that might contain malware.

The two advanced spam filtering solutions also have efficient spam detection mechanisms for inbound mail – using a series of front-end tests to detect 99.97% of spam email – while dual antivirus software offers protection against phishing attacks and malicious URLs within emails and their attachments.

The choice between the two advanced spam filtering solutions depends on each business´s individual circumstances. SpamTitan Gateway is a virtual appliance that is installed between a business´s firewall and its mail server. SpamTitan Cloud is a cloud-based anti-spam service that has a lighter maintenance overhead.

Both solutions – and their outbound spam filter – are easy to install and manage. Administrators can configure and monitor the performance of each solution via a browser-based platform, while a comprehensive suite of reporting options will alert administrators to any instance of spam email or virus either inbound or outbound.

How Does SpamTitan Email Filtering Work?

Every incoming email could be a potential threat, so it is essential for all messages to be subjected to a series of checks to determine whether the message is genuine and should be delivered or should be quarantined or rejected. SpamTitan uses a wide range of techniques to determine the authenticity of emails, as detailed in the diagram below:

How SpamTitan Spam Filtering Works

Comparison of Microsoft Office365 and SpamTitan

Many businesses use Microsoft Exchange or Office 365 for their email. Microsoft has incorporated several security features into its email offerings, although it is possible to greatly improve security with a more advanced anti-phishing, anti-malware, and anti-spam solution.

Office 365 security can be strengthened to provide greater protection against malware, ransomware, and phishing attempts through a defense in depth approach. SpamTitan offers superior email filtering by using predictive methods to block new variants of malware, zero-day attacks, and spear phishing attempts, making sure these malicious emails are quarantined or rejected rather than delivered to inboxes. Organizations that rely on the cybersecurity protections of Exchange or Office 365 are likely to find a significant number of email threats are still delivered to end users’ inboxes.

The image below summarizes some of the important features that are present in SpamTitan, which are not used by Office 365 or Exchange Online Protection:

Comparison of Office365 and SpamTitan

Try SpamTitan Free for Fourteen Days

If you are concerned about how your business might be affected by the lack of an outbound spam filter, we invite you to try SpamTitan free for fourteen days. Our offer consists of the choice of one of our advanced spam filtering solutions, full technical support and advice on how to configure your chosen filtering solution to achieve maximum effectiveness.

Our offer is entirely free of set up costs. There are no contracts to sign, credit cards required or commitment to continue with our service once the free trial period has expired. To find out more about our invitation, or to learn more about the benefits of an outbound spam filter, do not hesitate to contact our team of Sales Technicians today.

We also invite Managed Service providers and resellers to contact is and take advantage of our free offer. Both SpamTitan Gateway and SpamTitan Cloud are available in white label format for you to supply to your clients. We are also able to supply a range of APIs to integrate our advanced spam filtering solutions with existing third-party management products.


Do all anti-spam and anti-phishing solutions have an outbound spam filter?

It is becoming more common for spam filters to include outbound spam filtering, but many solutions still only scan inbound email. Since hackers often compromise email accounts and use them for spamming or malware delivery, it is strongly advisable to choose a spam filter with outbound scanning.

Can an outgoing spam filter protect against data theft?

An outgoing spam filter may include options that can protect against data loss. For instance, SpamTitan allows certain types of data to be tagged, so if any attempt is made to send them externally via email those attempts will be blocked and the security team will be alerted. It is also possible to prevent certain file types from being emailed externally.

Can outbound spam protection be configured differently for user groups?

SpamTitan has highly granular controls which can be applied at the organization, department, user group, or individual level. This is straightforward thanks to integration with Active Directory and LDAP. Most businesses will configure the solution with different inbound and outbound filtering controls for different user groups, often based on the level of risk.

What are whitelisting, blacklisting, and greylisting?

Whitelisting means all emails arriving at the mail server from a specified email address or domain will be delivered and blacklisting means all emails from a specific email address or domain will be blocked. Greylisting is a mechanism for detecting spam. Emails are initially rejected with a request for the message to be resent. Since mail servers used for spamming do not tend to respond to these requests, it is a good gauge of whether an email is genuine.

How much does a spam filter with outbound scanning cost?

The cost of an advanced spam filtering solution starts at around $1 per user per month, although there are solutions that cost considerably more. Even at $4 per user per month, that cost can be justified as it will be cheaper than having to deal with phishing attacks and malware infections. SpamTitan is at the lower end of the price spectrum yet offers excellent protection from the full range of email threats.