CONFIGURING


Restricting users from receiving Internet mail

Domino® provides SMTP intended recipient filters that let you control the users for whom the server accepts mail sent over SMTP connections. One filter triggers a directory lookup that enables the server to verify that an intended recipient exists before accepting a message. The other two filters let you explicitly specify the Internet addresses that can and cannot receive mail. To ensure that you don't unintentionally block desirable mail, use discretion when applying these settings.

About this task

During the SMTP conversation, the connecting host sends the Domino SMTP listener a RCPT TO command, which specifies the recipient's Internet address. Each of the Inbound Intended Recipient Controls works by examining the addresses specified as arguments to the RCPT TO command. For example, if you enable directory verification and the address specified in the RCPT TO command is in the local Internet domain, the SMTP listener refers to the Domino Directory to determine whether the address is valid. Messages for invalid addresses are rejected, preventing them from becoming "dead" messages in MAIL.BOX.

Note: Because enabling this setting results in messages for recipients not found in the directory being rejected, do not use this setting in environments that require mail to be forwarded to a smart host for further processing.

The "Allow messages" setting lets you list Internet addresses that are allowed to receive mail. If the RCPT TO command contains one of the specified addresses, the SMTP listener accepts the message; messages for all other recipients are rejected. The "Deny messages" setting lets you explicitly deny mail to certain addresses. If the RCPT To command contains a denied address, the SMTP listener rejects the message, but messages for all other recipients are accepted.

Note: If the server supports Local Part name lookups, users whose addresses are listed in the Deny field may still receive mail addressed to any alternate Internet addresses configured for them. To ensure greater control, specify the Internet address in each user's Person document and allow users to receive inbound mail destined for their fullname addresses only.

SMTP can resolve names for group types of Mail-only or Multi-purpose. When you create or modify the SMTP and Router settings in the Configuration Settings document, be sure to enter group names that have a group type of Mail-only or Multi-purpose. These groups must be in the primary directory. This applies to settings on the Restrictions tab, the SMTP Inbound Controls tab, and the SMTP Outbound Controls tab.

For information on restricting how Domino looks up recipient names, see the related links.

Procedure

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/SMTP -> Restrictions and Controls -> SMTP Inbound Controls tab.

6. Complete these fields , and then click Save & Close:


7. Reload the SMTP task, or update the SMTP configuration to put changes into effect.

Related concepts
Restricting SMTP inbound routing

Related tasks
Specifying how Domino looks up the recipients of incoming SMTP messages
Creating a Configuration Settings document
Stopping and starting the Domino SMTP service
Updating the SMTP configuration
Preventing unauthorized SMTP hosts from using Domino as a relay
Enabling DNS blacklist filters for SMTP connections
Restricting mail routing based on domain, organization, and organizational unit
Restricting who can send Internet mail to your users
Restricting users from sending mail to groups in the Domino Directory