Microsoft KB Archive/271575

= XCON: Internet Mail Service Uses the IMCEA Encapsulation Prefix String =

Article ID: 271575

Article Last Modified on 10/28/2006

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APPLIES TO


 * Microsoft Exchange Server 5.5 Standard Edition

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This article was previously published under Q271575



SUMMARY
This article describes the IMCEA encapsulation prefix string.



MORE INFORMATION
The Internet Mail Service uses an IMCEA encapsulation prefix string to identify address types other than Simple Mail Transfer Protocol (SMTP) that are sent over the Internet Mail Service.

NOTE: The encapsulation prefix is case-sensitive, and must be uppercase to function properly.

Some mail servers may not preserve the case of the encapsulation prefix string, and therefore violate Request for Comment (RFC) 821, Section two (The SMTP Model) which states:

SMTP implementations must take care to preserve the case of user names as they appear in mailbox arguments.

The encapsulation prefix string is contained in a mailbox argument, as defined by RFC 821.

If an SMTP server that is transmitting these encapsulated addresses does not preserve the case, the Internet Mail Service does not recognize the messages as encapsulated, and therefore generates non-delivery reports (NDRs) for them. This behavior causes folder replication over the Internet Mail Service to fail, and any messages for connected sites that are sent over the Internet Mail Service are not received.

Additional query words: imceaex imc ims

Keywords: kbinfo KB271575

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