When you configure TNEF conversion options for a remote domain, those TNEF conversion options are applied to all messages sent to that domain. For remote domains in your organization, you have the following configuration options for TNEF conversion:

• TNEF use enabled   TNEF is used for all messages sent to the remote domain.
  
• TNEF use disabled   TNEF is never used for any messages sent to the remote domain.
  
• Unspecified   TNEF messages aren't specifically allowed or prevented for recipients in the remote domain. Whether TNEF messages are sent to recipients in the remote domain depends on the specific setting on the mail contact or mail user, or the setting specified by the sender in Outlook. This is the default setting.
  

In Microsoft Exchange 2010, you can set the TNEF conversion options for messages sent to a remote domain in the Exchange Management Shell or on the Remote Domains tab in the Exchange Management Console (EMC). For more information about configuring TNEF options for a remote domain, see the following topics:

• Configure Remote Domain Properties
  
• Set-RemoteDomain
  

When you configure TNEF conversion options for a mail contact or a mail user, those TNEF conversion options are applied to all messages sent to that specific recipient. For mail contacts and mail users in your organization, you have the following configuration options for TNEF conversion:

• Always   TNEF is used for all messages sent to the recipient.
  
• Never   TNEF is never used for any messages sent to the recipient.
  
• Use default settings   TNEF messages aren't specifically allowed or prevented for the mail user or mail contact. Whether TNEF messages are sent to the recipient depends on the specific setting for the corresponding remote domain or the setting specified by the sender in Outlook. This is the default setting.
  

  Note:
  In both the EMC and the Shell, the TNEF conversion settings are referred to as MAPI rich text format.

You can set the TNEF conversion options for messages sent to mail users and mail contacts in the Shell or in the Recipient Configuration node in the EMC. For more information about configuring TNEF options for these recipient types, see the following topics:

• Configure Mail Contact Properties
  
• Configure Mail User Properties
  
• Set-MailContact
  
• Set-MailUser
  

Senders can control the default TNEF message conversion options for TNEF messages sent to all recipients outside the Exchange organization. These options are called Internet message format options. The options only apply to remote recipients, and not to recipients in the Exchange organization.

Note:
The following options define how messages containing Outlook rich text are handled when sent to external recipients. If the message format you're using is HTML or plain text, these settings don’t apply.

You have the following TNEF conversion options in Outlook:

• Convert to HTML format   This is the default option. Any TNEF messages sent to remote recipients are converted to HTML. Any formatting in the message should closely resemble the original message. MIME-encoded HTML messages are supported by many, but not all, e-mail clients.
  
• Convert to Plain Text format   Any TNEF messages sent to remote recipients are converted to plain text. Any formatting in the message is lost.
  
• Send using Outlook Rich Text Format   Any TNEF messages sent to remote recipients remain TNEF messages.
  

These options can be configured in Outlook by navigating to Tools > Options > Mail Format, and then clicking Internet Format.

Senders can also control the default TNEF message conversion options for TNEF messages sent to specific recipients outside the Exchange organization. These options are called Internet recipient message format options. The options only apply to remote recipients stored in your Contacts folder, and not to recipients in the Exchange organization. You have the following TNEF conversion options for remote recipients in your Contacts folder:

• Let Outlook decide the best sending format   This is the default setting. This setting forces Outlook to use the TNEF conversion option that's specified by the default Internet format. The possible values are Convert to HTML format, Convert to Plain Text format, or Send using Outlook Rich Text Format. Therefore, the TNEF message may be left as TNEF, converted to HTML, or converted to plain text. If you want to make sure that the TNEF message remains TNEF for this recipient, you should change this setting from Let Outlook decide the best sending format to Send using Outlook Rich Text format.
  
• Send Plain Text only   Any TNEF messages sent to the recipient are converted to plain text. Any formatting in the message is lost.
  
• Send using Outlook Rich Text format   Any TNEF messages sent to remote recipients remain TNEF messages.
  

These options can be configured for a contact in Outlook by opening that contact and then double-clicking the E-mail field and selecting Internet format.

Exchange 2010 uses the order of precedence as described in the following list to determine the TNEF conversion options for outgoing messages sent to recipients outside the Exchange organization:

1. Outlook settings
   
2. Mail user or mail contact settings
   
3. Remote domain settings
   

The list specifies the order of precedence from lowest to highest. A setting made at a higher level overrides a setting made at a lower level.

Exchange never sends Summary Transport Neutral Encoding Format (STNEF) messages to external recipients. Only TNEF messages can be sent to recipients outside the Exchange organization.