\begin{itemize}
\item   X.400 (1984) P1 protocol.
\item	X.400 (1988) P1 protocol.
\item  	Simple mail transfer protocol (SMTP), conformant to
  host requirements.
\item   JNT mail (grey book) Protocol.
\item   UUCP mail transfer.
\item	DECNET Mail-11 transfer
\item	Distribution list expansion and maintenance, using either a
  file based mechanism or an X.500 directory.
\item   RFC~822-based local delivery.
\item	Delivery time processing of messages.
\item	Conversion between X.400 and RFC~822 according to  the latest
  revision of RFC~1148, known as RFC~1148bis.
\item	Conversion support for reformatting body parts and headers.
\item	X-Window and line-based management console.
\item   Message Authorisation checking.

\item   Reformatting support for ``mail hub'' operation.
\item	X.500-based distribution list facility using the QUIPU 
	directory.
\item	FAX interworking
\end{itemize}
