[CalendarServer-users] strange calendar/dovecot interaction

[Jim Reid]

This is a bit off-topic since it involves the official Apple calendar
server. Sorry.

I bought OSX Server, started the calendar service and have got calendar
data imported to the server and visible to client apps. So far, so good.

However, my logs are filling up with authentication failures and I don't
have a clue what is wrong or why these are happening. It's not clear why
the calendarserver is trying to speak to my dovecot IMAP server. Does
anyone know what's wrong or how to troubleshoot and fix this?

Every ~30 seconds, calendarserver reports:

% tail /Library/Server/Calendar and Contacts/Logs/error.log 
2016-01-07 22:42:38+0000 [-] [caldav-1]  [IMAP4DownloadProtocol \
	(TLSMemoryBIOProtocol),client] \
	[txdav.caldav.datastore.scheduling.imip.inbound.IMAP4DownloadProtocol#error] \
	IMAP login failed for com.apple.calendarserver
2016-01-07 22:43:08+0000 [-] [caldav-1]  [IMAP4DownloadProtocol \
	(TLSMemoryBIOProtocol),client] \
	[txdav.caldav.datastore.scheduling.imip.inbound.IMAP4DownloadProtocol#error] \
	IMAP login failed for com.apple.calendarserver
2016-01-07 22:43:39+0000 [-] [caldav-1]  [IMAP4DownloadProtocol \
	(TLSMemoryBIOProtocol),client] \
	[txdav.caldav.datastore.scheduling.imip.inbound.IMAP4DownloadProtocol#error] \
	IMAP login failed for com.apple.calendarserver

And in the dovecot logs, I get this:

Jan  7 22:43:14 hutch dovecot[63067]: imap-login: Disconnected \
	(auth failed, 2 attempts in 4 secs): user=<com.apple.calendarserver>, \
	method=PLAIN, rip=195.54.233.70, lip=195.54.233.70, TLS, session=<dSvTQ8YoXQDDNulG>
Jan  7 22:43:40 hutch dovecot[63067]: auth-worker(65378): Error: \
	pam(com.apple.calendarserver,195.54.233.70): pam_acct_mgmt() failed: permission denied
Jan  7 22:43:44 --- last message repeated 1 time ---
an  7 22:43:44 hutch dovecot[63067]: imap-login: Disconnected \
	(auth failed, 2 attempts in 4 secs): user=<com.apple.calendarserver>, \
	method=PLAIN, rip=195.54.233.70, lip=195.54.233.70, TLS, session=<VBuoRcYocgDDNulG>
Jan  7 22:44:11 hutch dovecot[63067]: auth-worker(65378): Error:
pam(com.apple.calendarserver,145.54.233.70): pam_acct_mgmt() failed: permission denied
Jan  7 22:44:19 --- last message repeated 1 time ---

The dovecot server is configured to use PLAIN authentication with PAM and CRAM-MD5,
both over TLS. The calendar server is using the credentials for my MacOS login. Which
is presumably accessible via PAM for dovecot's imap-login. Mail accounts use MD5
challenge response (again over TLS) for SMTP and IMAPS logins. However my mail MD5
"password" is not the same as my MacOS password even though the user name is unchanged.

I suppose the two passwords could be aligned, but I'd prefer to keep these separated.

I'd be grateful for any advice and suggestions, thanks.