SMTPGuard™ is an application layer firewall dedicated to protect SMTP-standard mail server against the attacks such as:

• overloading - Deny-Of-Service and Distributed Deny-Of-Service,
• attacking SMTP server by using malformed SMTP commands,
• mail-bombing (it automatically and intelligently blocks dangerous connections for a period of time),
• illegal redirection (relay),
• sending mail to special users and groups,
• opening too much threads,
• establishing too many concurrent connections,
• establishing too frequent connections,
• establishing connections from specified IPs or hosts,
• establishing too long connections,
• establishing connections with dangerous servers,
• waiting too much between commands,
• sending too many SMTP commands,
• fragmented network packets attacks.

• Checks if sender domain exists (DNS checking).
• Allows setting only a sub-list of users or groups with possibility of sending mails outside the corporation.
• It can emulate behavior of all other servers (identity spoofing) and work in a hidden mode. It can set any server response.
• It controls the SMTP standard.
• It permits to run every command when specified conditions occurr (e.g. immediately informs the admin about ane efforts to hack the server).