SMTPGuard™ is a application layer firewall dedicated to protect SMTP-standard mail server against a lot of 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 to much threads,
• establishing to much concurrent connections,
• establishing to frequent connections,
• establishing connections from specified IPs or hosts,
• establishing to long connections,
• establishing connections with dangerous servers,
• waiting to long time between commands,
• sending to much SMTP commands,
• fragmented network packets attacks.

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