CleanMail System Requirements

Seamless Integration Into Your E-Mail Environment

CleanMail's transparent proxy architecture was designed to make the integration into existing e-mail environments easy and straight-forward. CleanMail Server allows you to configure an unlimited number of SMTP/POP3 proxy ports or POP3 connectors (full multi-domain support). CleanMail Antispam can be installed on your existing mail server and does not require additional hardware.

Configuration Options

Here is just a small selection of configuration options available in CleanMail:

Network Configuration Options

CleanMail Server can either be installed on separate hardware or on the same machine as your current SMTP/POP3 mail server. It works with any SMTP or POP3 mail server or POP3-to-SMTP connector.

SMTP Proxy Options

• IP address/port number for incoming mail
• Outgoing mail server/port number
• Maximum resource usage
• Open relay protection: list of recipient address patterns where email is accepted
• Protection against directory harvesting attacks
• (optional) List of recipient address patterns with spam checking enabled
• (optional) SMTP Traffic limiting, to prevent mail flooding

POP3 Proxy Options

• Account and POP3 server information

POP3 Connector Options

• POP3 account and POP3 server network name or address
• Mail account and SMTP server network name or address

Available Mail Filters

• DNS Blacklist filter
• Attachment filter
• SpamAssassin Anti-Spam filter
• Anti-Virus filter: ClamWin already included as default, support for third-party anti-virus software from many vendors
• Delay Filter
• Mail storage: save all incoming mail to disk
• Spam trap filter: automatically learn spam mails sent to a honeypot address
• User-configurable filters

Filter Options

• Policy: reject/delete, reject/redirect, reject/deliver, accept/deliver, configurable reply messages
• Recipient address patterns: where to apply a filter

All filters allow to choose what happens with a mail if the filter finds unwanted content, such as a virus, or spam.

• accept/deliver (check disabled): A filter returns this result if the filter has been disabled for all recipients of a message.
• accept/deliver: The filter did not find unwanted content.
• accept/deliver (skip size exceeded): Some filters do not check mails larger than a configurable size. For example, spam mails are typically small, so the SpamAssassin filter by default passes large mails without checking.
• accept/deliver (junk): The filter found unwanted content, but the mail is accepted and delivered nonetheless.
• reject/deliver: The filter found unwanted content. Receipt of the mail is rejected with a configurable Mail Rejection Message. The message is still delivered to its recipients. Some filters (such as the SpamAssassin filter) tag the message, so they can be quarantined by the mail server using filtering rules.
• reject/redirect: The filter found unwanted content. Receipt of the mail is rejected. The MTA that connects to CleanMail is supposed to notify the user with a configurable Mail Rejection Message. The mail is redirected to a quarantine account you can configure.
• accept/redirect: The filter found unwanted content. The mail is accepted. The mail is redirected to a quarantine account you can configure.
• reject/delete: The filter found unwanted content. Receipt of the mail is rejected. The MTA that connects to CleanMail is supposed to notify the user with a configurable Mail Rejection Message. The mail is deleted.
• accept/delete: The filter found unwanted content. Receipt of the mail is acknowledged, but the mail is deleted. The mail simply vanishes, the sender is not notified, and the recipient never sees it.
• delete (unexpected client disconnect): The client disconnected without waiting for the mail server to acknowledge receipt of the message. The mail was probably spam, so good riddance. A legitimate sender will try to resend the message later.
• reject/delete (mail too large): The mail was larger than the message size limit you have configured. The message is rejected, and the MTA that connects to CleanMail is supposed to notify the user with a configurable Mail Rejection Message.

SpamAssassin™ Configuration Options

• Required score (how many filtering points are needed to flag a mail as spam?)
• Flag spam in subject line yes/no, configurable text

Read more about countless other SpamAssassin™ configuration options here: http://spamassassin.apache.org/

Supported Standards

CleanMail complies to the following standards:

• Simple Mail Transfer Protocol (SMTP): RFC 2821
• Post Office Protocol Version 3 (POP3), RFC 1939
• Internet Message Format: RFC 822, RFC 2822, RFC 2045-2049, and RFC 2231
• SMTP Service Extensions, RFC 1869
• SMTP Service Extension for Authentication, RFC 2554
• SPF (Sender Policy Framework)