MailEnable Features - Anti-spam & Security

MailEnable includes powerful anti-spam and security features to help keep your data secure, your server running smoothly, and your inbox free from junk mail.

Bayesian Filtering

Bayesian filtering is a method of spam prevention. It operates by rating the probability of incoming mail being spam by looking at words or character strings contained in the email as well as the entire context of the email. Bayesian filters can be 'trained' to identify spam by building up libraries of 'good' and 'bad' mail (spam). There is also the ability to "auto-train" the Bayesian dictionary. This means the filter is continually improving by 'learning' to identify spam and good mail based on emails that are passing through the server.

Reverse DNS Blacklisting

Reverse DNS Blacklisting allows you to validate those sending mail against a list of potential spammers. You can select which Real Time Blacklists (RBL's) providers you want to use. You should enable only the providers that you need, as this does impact on performance. You should also review which providers are most appropriate by reviewing their web sites.

Abuse Prevention

System Administrators can configure global thresholds for message throughput. Administrators can save server-wide settings that limit the number of messages sent by a user.

These settings can be overridden as required on a per postoffice or mailbox basis. By default, users are capped at 100 messages per hour.

MailEnable can also permanently block IP addresses if they issue too many invalid commands to the server. MailEnable can lock out accounts after too many failed password attempts. MailEnable services maintain a list of IP addresses and record any significant activity. This record can then be used to determine whether the source addresses have violated a security policy and should be temporarily blocked. As an example, an IP address that is connecting and attempting to spoof user accounts might be blocked for an hour as a means of protecting password dictionary attacks.

Domain Keys (DKIM)

MailEnable's Domain Keys (DKIM) implementation provides inbound validation and outbound signing of messages. The extensive filtering provided by MailEnable allows you to discriminate messages according to their domain key validation. Administrators can either use inbuilt simple criteria or tailor complex scripts according to filtering requirements.

URL Blacklist Content Filtering

The MailEnable SMTP Connector scans the content of messages as they are received and can identify whether the contents of the messages contain offensive URLs by looking up their IP address against DNS blacklist providers.

Message Filtering

Use message filters to search messages for words or phrases and delete or quarantine them before they are delivered to the user. Mark messages as spam so that they are placed directly into the recipients Junk Mail folder.

Filters can also be configured to move or delete messages based on content and much more.

Sender Policy Framework (SPF)

Sender Policy Framework (SPF) prevents the 'spoofing' or forging of mail addresses and makes it easier to identify spam, worms and trojans.

SPF requires a DNS record to specify which machines are authorized to transmit mail for that particular domain. Therefore the mail server receiving mail can determine whether a message came from a domain other than the one claimed by the sender.

Secure Data Transmission

MailEnable services all support SSL to protect sensitive data as it is accessed, and the SMTP service provides outbound TLS support, allowing the secure encrypted transmission of messages to remote SMTP servers.

Relay Control

Without relay control, spammers can utilise your server in order to send out their junk mail, making it look as though you were the origin of spam. MailEnable has inbuilt relay control that prevents your server being used as a relay for spam.

Anti-virus Scanning

As well as supporting an impressive array of third party plug-in scanners, MailEnable includes a pre-configured installation of ClamAV.

Compatible with 3rd Party Spam Filtering

MailEnable can also work in conjunction with various third party anti-spam applications.

Learn more

End User Blacklisting And Whitelisting

MailEnable allows whitelisting to occur as messages arrive via SMTP. This prevents messages from these domains from being delayed by greylisting. This feature can be enabled or disabled as required.

Similarly, end users are able to reject messages from a given domain or user at the SMTP level. A list of blacklisted email addresses and domains can be configured via the webmail client. When a blacklisted sender attempts to send the message, the SMTP connector will immediately refuse the delivery attempt.


Greylisting helps reduce spam by delaying messages for a short period of time when the sender is not someone who has recently sent to that destination. A large percentage of spammers do not retry sending a delayed message, but normal mail servers will, so the message will come through on the next attempt.

Spam, Anti-virus & Message Filtering Services





3rd Party Plug-in Filters        
IP Address Access Control        
IP Address Whitelisting        
Reverse DNS Blacklisting        
Require PTR DNS Record for Unauthenticated Inbound Connections        
Check for Valid Sender Domain        
Authenticated senders must use a valid email address        
Restrict the number of recipients per email        
Limit the number of recipients users can send to per hour        
TLS SMTP Outbound support        
Configure Global Message Filters        
Bayesian Anti-spam Filtering        
Sender Policy Framework (SPF)        
Scripted Filtering        
Spam protection filter that weights email messages for Webmail users        
URL Blacklisting        
Report IP of spam source via Webmail to block future spam        
Email addresses and domains can be blacklisted and whitelisted in Webmail        
Automatic Outbound Whitelisting        
Abuse protection from dictionary attacks        
Anti-virus Scanning (3rd Party)        
Event Auditing        
Abuse Policy        
Failed Auth Account Lockout        
Anti-virus scanning per Post Office        
Reverse DNS Blacklisting per Post Office        
Message Filtering (per mailbox)        
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