184.108.40.206 Address Elements
In general, address elements are generated in a pure MIME message only and not in a TNEF message. However, when a TNEF message is generated, all address elements of messages that are included as attachments of the top-level message are generated in the TNEF message only, as specified in [MS-OXTNEF]. This is because no MIME entity corresponds to the attached messages; the attached messages are wholly contained in the TNEF message.
MIME writers MUST generate e-mail addresses for MIMErecipients (2) in compliance with the address requirements specified in [RFC2822]. For example, in cases where a display name is generated in a MIME address header (2), MIME writers SHOULD use the encoding specified by [RFC2047] to encode any display name value that has characters that are not allowed in a MIME header (2), as specified in [RFC2822]; however, MIME writers MAY<2> generate display names with quotes around all but the non-ASCII characters, in order to accommodate clients that are not compliant with the display name encoding specified in [RFC2047]. MIME writers MAY<3> only generate display names for recipients (2) when the SMTP policy for the domain is configured to preserve the sender's address on the message, which is turned off by default. These addresses are always SMTP addresses. When a client supports other types of e-mail addresses through the PidTagAddressType property ([MS-OXOABK] section 220.127.116.11), MIME writers SHOULD<4> use Internet Mail Connector Encapsulated Address (IMCEA)encapsulation of the e-mail address to form an SMTP address, as specified in section 18.104.22.168.8.