Exchange
Fun with Microsoft Exchange.
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Exchange protocol bugs
Microsoft Exchange server has several protocol bugs which you may need to work around.
Failure of plain authentication
You get the following error message: Retrying PLAIN authentication after AUTHENTICATE failed. This is because Microsoft Exchange protocol mistakenly advertises plain authentication even though it does not support it. You need to force the email client to ignore this. E.g. with alpine
disable-these-authenticators=PLAIN
Kerberos authentification failure
You get the following error messages: Unknown Kerberos failure: An invalid name was supplied and Kerberos mechanism status: Hostname cannot be canonicalized. This is because Microsoft Exchange protocol mistakenly advertises kerberos authentication even though it does not support it. E.g. alpine users need to add this option
disable-these-authenticators=GSSAPI
Workaround both problems
To work around both problems you need to disable plain authentication as well as Kerberos host authentication. E.g. with alpine
disable-these-authenticators=PLAIN,GSSAPI
Message to save shrank!
You get the following error message: Message to save shrank!. This is because Exchange server often does not compute the message size properly (also see alpine changelog). To the email client this looks like the message was not transferred completely. alpine users need to upgrade to a recent version which allows you to ignore this error and proceed with saving the message.
