| Business Mail Anti-spam & Security
Business Mail 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 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.
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.
Business Mail can also permanently block IP addresses if they issue too many invalid commands to the server. Business Mail can lock out accounts after too many failed password attempts. Business Mail 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)
Business Mail’s Domain Keys (DKIM) implementation provides inbound validation and outbound signing of messages. The extensive filtering provided by Business Mail 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 Business Mail 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.
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.
Secure Data Transmission
Business Mail services all support SSL to protect sensitive data as it is accessed, and the SMTP service provides outbound TLS/SSL support, allowing the secure encrypted transmission of messages to remote SMTP servers.
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.
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. Business Mail has inbuilt relay control that prevents your server being used as a relay for spam.
As well as supporting an impressive array of third party plug-in scanners, Business Mail includes a pre-configured installation of ClamAV.
Compatible with 3rd Party Spam Filtering
Business Mail can also work in conjunction with various third party anti-spam applications.
End User Blacklisting And Whitelisting
Business Mail 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.