Supporting outbound SMTP extensions

Domino® supports outbound extended SMTP (ESMTP) features to interact with other messaging servers. These extensions are controlled in the Configuration Settings document.


  1. Make sure you already have a Configuration Settings document for the server(s) to be configured.
  2. From the Domino® Administrator, click the Configuration tab and expand the Messaging section.
  3. Click Configurations.
  4. Select the Configuration Settings document for the mail server or servers you want to administer, and click Edit Configuration.
  5. Click the Router/SMTPAdvancedCommands and Extensions tab.
  6. Complete these fields, and then click Save & Close:
    Table 1. Outbound SMTP Commands and Extensions fields



    SIZE extension

    Choose one:

    • Enabled - (default) If the destination SMTP host also supports the SIZE extension, Domino® declares the estimated size of messages before transfer.
    • Disabled - Domino® does not declare message size before transferring messages to another SMTP server.

    Pipelining extension

    Choose one:

    • Enabled - (default) If the remote SMTP host also supports pipelining, Domino® sends multiple SMTP commands in the same network packet to improve performance.
    • Disabled - Domino® sends each SMTP command in a separate packet.

    DSN extension

    Choose one:

    • Enabled - When sending a message to a server that also supports the DSN extension, Domino® appends a NOTIFY parameter to the SMTP RCPT TO command to request a particular type of delivery status notification for the message. For messages sent from Notes® clients, Domino® uses the Delivery report options specified by the client (Confirm delivery; Trace entire path; Delivered) to determine the type of DSN requested.
    • Disabled - (default) Domino® does not send DSN requests.

    8-bit MIME extension

    Choose one:

    • Enabled - When sending a message to a remote server that also supports 8-bit MIME, Domino® improves performance by sending messages containing multinational characters as is, without first encoding them.
    • Disabled - (default) Domino® encodes messages containing 8-bit characters as 7-bit ASCII before sending.


The change takes effect after the next Router configuration update. To put the new setting into effect immediately, reload the routing configuration.