Topic Last Modified: 2007-01-23

You can configure the Simple Mail Transfer Protocol (SMTP) virtual server to provide the authentication credentials required by a receiving server. Three types of authentication are available: Anonymous access, Basic authentication (clear text), and Integrated Windows authentication. Anonymous access requires no user name or password. With the Basic authentication option, the account name and password that is used to authenticate with the server you're connecting to are transmitted in clear text. The Integrated Windows authentication option requires a Windows account name and password.

The Outbound Security option that is set for the SMTP virtual server can be overridden for a specific remote domain. This enables you to set the virtual server authentication level to handle most of the transmissions, while allowing exceptions for individual addresses. The following table describes common configuration scenarios.

Note:
For information about how to encrypt outgoing messages, see Requiring TLS Encryption.

SMTP transmissions Authentication option

Messages are commonly sent to multiple addresses.

Disable authentication for the SMTP virtual server. If attempts to deliver messages to an address space fail because of authentication requirements, create a remote domain entry for that address space. Enable authentication for the remote domain at the same level required by the receiving server.

Messages are commonly sent to one address, which requires authentication.

Determine what level of authentication is required to connect. Then enable authentication for the SMTP virtual server using the same level. If you want to send messages to other addresses, set up remote domains and set different authentication options. If you use this option, it is likely that the account name that is used is the one that identifies the computer setup as the smart host.

Procedure

To disable authentication for outgoing messages

  1. On the Delivery tab, click Outbound Security to open the Outbound Security dialog box.

  2. Click Anonymous access.

  3. Clear all other options.

To set Basic authentication for outgoing messages

  1. On the Delivery tab, click Outbound Security to open the Outbound Security dialog box.

  2. Click Basic authentication.

  3. Under User name and Password, type the account name and password that will grant you access to the computer that you are connecting to.

Important:
If Basic authentication is your only authentication method, we strongly recommend that you also require Transport Layer Security (TLS) encryption to avoid unauthorized detection of user names and passwords.

To set Integrated Windows authentication for outgoing messages

  1. On the Delivery tab, click Outbound Security to open the Outbound Security dialog box.

  2. Select Integrated Windows Authentication.

  3. Under Account and Password, type a Windows account name and password that will grant you access to the computer that you are connecting to.

  • Requiring Authentication for Incoming Connections
  • Requiring TLS Encryption