I use hmailserver as an internal Mail Server.
Mail is received by an external Mail Server (1und1), hmailserver pop3 downloads from external account.
Mail is delivered by SMTP relayer smtp.1und1.de

Works fine.

Now i want to sync the external Sent folder with the internal hmailserver Sent Folder.
Because sometimes Users (on the Road) will send Mails directly via the external Mail-host.

imapsync --host1 imap.1und1.de --user1 xy@domain.de --password1 xyz --ssl1 --host2 hmailserver --user2 xy@domain.de --password2 xyz --tmpdir c:\hmailserver --usecache --folder Sent --ssl2

works fine.

But i want to use Active Directory.
I use internal hmailserver Accounts with Active Directory Auth plus an external account each.

imapsync --host1 imap.1und1.de --user1 xy@domain.de --password1 xyz --ssl1 --host2 hmailserver --user2 xy@domain.de --password2 domainpwd --tmpdir c:\hmailserver --usecache --folder Sent --ssl2

Works fine, but if the user changes the domainpwd I'd have to change the imapsync script.

That's why I'd like to use authuser: A hmailserver account 'madmin' (no active Directory) with Administration level 'Server' or 'Domain'

->Question #1: Can the 'madmin' user authenticate with his PWD and access the IMAP Folders of other users?
I read that cyrus or zimbra have 'superusers' like that.

IF yes then
->Question #2:

I try:
imapsync --host1 imap.1und1.de --user1 xy@domain.de --password1 xyz --ssl1 --host2 hmailserver --user2 xy@domain.de --authuser2 madmin@domain.de --tmpdir c:\hmailserver --usecache --folder Sent --ssl2

But:
host hmailserver says it has NO CAPABILITY for AUTHENTICATE PLAIN
host hmailserver says it has NO CAPABILITY for AUTHENTICATE LOGIN


Info: turned ON syncinternaldates, will set the internal dates (arrival dates) o
n host2 same as host1.
Info: will try to use LOGIN authentication on host1
Info: will try to use PLAIN authentication on host2
Host1: imap server [imap.1und1.de] port [993] user [xy@domain.de]
Host2: imap server [colmailsrv1] port [993] user [xy@domain.de]
What's the password for madmin@domain.de@hmailserver?
Banner: * OK IMAP server ready H mimap7 90986
Info: host imap.1und1.de says it has CAPABILITY for AUTHENTICATE LOGIN
Info: success login on [imap.1und1.de] with user [xy@domain.de] aut
h [LOGIN]
Banner: * OK IMAPrev1
Info: host hmailserver says it has NO CAPABILITY for AUTHENTICATE PLAIN
Info: frequently PLAIN is only supported with SSL, try --ssl or --tls options
Failure: error login [hmailserver] with user [xy@domain.de] auth [P
LAIN]: 2 NO Unsupported authentication mechanism.
Failure: error login [hmailserver] with user [xy@domain.de] auth [P
LAIN]: 2 NO Unsupported authentication mechanism.


Best Solution: external Imap accounts with folder support in hmailserver.

Your imapsync tool confused something. hMailServer does not say that AUTH LOGIN is not supported. Your tool failed to realize that AUTH LOGIN is standard IMAP4rev1 feature and server does not have to declare it. Servers declare only disabled LOGIN capabilities.

hMailServer does not support sslv1 or sslv2. You need SSLv3 or TLSv1 client and you should make sure that your client does not confuse TLS with StartTLS.

Question #1: ...
No. If you know standard which implements this feature, you should also know which servers support it.

Question #2: ....
Answer is related to question no 1 and one of error messages you are seeing. SASL PLAIN is not supported by hMailServer and if you need superuser access to other users' mailboxes, you need starttls and sasl plain.