ISPmanager allows you to protect your mailboxes from unwanted emails. The control panel utilizes built-in tools provided by Exim, Greylisting and SpamAssassin filters, and the antivirus ClamAV. To install them go to Settings → Features. Learn more in Install a mail server.
Exim allows configuring the rules to receive or reject emails from different senders. The system will accept emails from the senders that are allowed to send messages to the mail server and denies them from those who are blacklisted.
To add a new rule to the whitelist:
The whitelist is kept in /etc/
To add a new rule to the blacklist and reject unwanted emails:
The blacklist is kept in /etc/
DNSBL (DNS blacklist) is a list of domain names and IP addresses that are normally used for spam protection. This tool allows you to block messages from specific systems that have a history of sending spam.
Perform the following steps to add a DNSBL list:
Recommeded black lists:
The DNSBL that you have added are kept in /etc/
Greylisting is a prevention method that allows filtering out spammers with special programs.
The receiving mail server rejects a message, informs a sender that the message cannot be delivered immediately and asks to try again later. The sending server of a legitimate user will retransmit the message. Such mail servers are put on the white list and will be delivered without any delay. The servers that spammers use generally will not respond, because the spammer's goal is to disseminate millions of messages quickly and not have to keep track of those failed to reach their destination. In ISPmanager Graylisting is run by Postgrey.
To add a sender into the whitelist and do not check its emails with Greylisting:
The white list is kept in /etc/postfix/postgrey_whitelist_clients on CentOS and in /etc/postgrey/whitelist_clients on Debian and Ubuntu.
SpamAssassin is an email filter that uses text analysis to block known spam senders. Corresponding records are added into message headings so that a user can filter email messages into different directories of the mail program. The following is an example configuration for Mozilla Thunderbird:
ClamAV is an antivirus that checks incoming email. Emails with infected files are rejected.
By default, the control panel performs the following operations: