msexchange channel keyword may be used on TCP/IP
channels to tell PMDF that this is a channel that communicates with MS
Exchange gateways and clients. When placed on an incoming TCP/IP
channel which has SASL enabled (via a
mustsaslserver keyword), it causes PMDF's SMTP server to
advertise AUTH using an "incorrect" format (based upon the
original ESMTP AUTH specification, which was actually incompatible with
correct ESMTP usage, rather than the newer, corrected AUTH
specification). Some MS Exchange clients, for instance, will not
recognize the correct AUTH format and will only recognize the incorrect
msexchange channel keyword also causes advertisement
(and recognition) of broken TLS commands.
nomsexchange is the default.