PresentationDTM SMTP Interceptor
The DTM SMTP Interceptor helps protect your HCL Domino mail server by intercepting and blocking unwanted incoming SMTP connections.
Its filtering engine applies configurable rules, while a dedicated HCL Notes database allows Domino administrators to manage whitelists and blacklists for domains and IP addresses.
On Linux systems, the interceptor can work alongside Fail2ban to block offending IP addresses at the system level. It records hostnames and IP addresses in a format compatible with HCL Domino SMTP logs and Fail2ban filters, helping administrators manage unwanted connections more effectively.
- Fail2ban integrated to Linux is used by the system
to block incriminated inbound IP addresses. The DTM
SMTP Interceptor records hostnames and IP addresses
in the appropriate format for use with Domino-SMTP
or Domino filters applied by Fail2ban, as logged in
HCL Domino logs. This ensures streamlined management
of unwanted connections and enhances security
measures for the mail server.
ProductDTM SMTP Interceptor Configuration
Configuration is managed through documents in an HCL Notes database. Changes take effect dynamically, without requiring a restart of the HCL Domino server.
Whitelisted Domains or IP addressesAdministrators can explicitly allow selected domains and IP addresses (IPv4, IPv6, or CIDR ranges), even when blacklist rules are enabled.
Blacklisted Domains or IP addressesAdministrators can block specific domains and IP addresses (IPv4, IPv6, or CIDR ranges).
Administrators can blacklist certain SMTP commandsAdministrators can blacklist certain SMTP commands or restrict the set of allowed SMTP commands. For standard SMTP commands, specific commands can be denied even if they do not have parameters.
EHLO/HELOAdministrators can reject empty EHLO/HELO commands or block specific client identifiers.
MAIL FROM FilteringAdministrators can block SMTP connections based on the sender address specified in the MAIL FROM command.
recipientsAdministrators can limit the number of accepted recipients per message or block specific recipient addresses.