Enabling and disabling SMTP verification of recipient email addresses

To enable or disable SMTP verification of recipient email addresses:

In the main window of the application web interface, open the management console tree and select the Settings section and MTA subsection.
Open the Advanced Settings section.
Click the Reject messages for unknown recipient domains or Reject messages for unverified recipients link to open the Advanced MTA settings window.
In the Reject messages for unknown recipient domains list, select one of the following values:
- Yes if you want Kaspersky Secure Mail Gateway to reject the message delivery request if the RCPT TO domain name does not contain MX records of the DNS server and the DNS address or MX record is distorted (for example, a zero-length address of the MX host is specified).
- No if you do not want Kaspersky Secure Mail Gateway to reject the message delivery request if the RCPT TO domain name does not contain MX records of the DNS server and the DNS address or MX record is distorted (for example, a zero-length address of the MX host is specified).
The default value is Yes.
To the right of the Reject messages for unverified recipients setting name, select one of the following options:
- None, if you do not want to reject messages to unverified addresses.
- Reject for unverified recipients, if you want to reject the message delivery request if the RCPT TO is not available.
- Reject for recipients not in valid list, if you want to reject the message delivery request if the RCPT TO address is not in the list of valid domains for its domain class.
Click the OK button.

The Advanced MTA settings window closes.

SMTP verification of recipient email addresses is not performed when Kaspersky Secure Mail Gateway receives messages from trusted network hosts.

Intense mail traffic can increase the load on the mail server due to transmission of failed message delivery notifications.