Siehe auch:
https://reichert.pro/kopano-installation-auf-basis-von-univention/
https://www.univention.de/blog-de/2018/06/einrichtung-eines-leistungsstarken-ucs-home-server-mit-owncloud-kopano-lets-encrypt/

https://docs.nextcloud.com/server/14/admin_manual/issues/general_troubleshooting.html#service-discovery

Änderungen:

1. Zeile 113: Anzeige der Public Contact aktiviert
   

   /etc/kopano/webapp/config.php

   define("DISABLE_PUBLIC_CONTACT_FOLDERS", false);

2. Einmal update-ca-certificates ausführen, damit das Let's Encrypt Root Zertifikat in /etc/ssl/certs verlinkt wird.
3. Let's Encrypt Zertifikat für den IMAP Server kopieren:
   

   cd /etc/kopano/ssl
   cp /etc/univention/letsencrypt/signed_chain.crt cert.pem
   cp /etc/univention/letsencrypt/domain.key private.key
   chown kopano:kopano *
   chmod 640 cert.pem
   chmod 600 private.key
   service kopano-gateway stop
   service kopano-gateway start
   

Für alle User erledigen:

• Kategorien benennen und einrichten
• Öffentliche Ordner einbinden

Kopano Web Meetings is now installed and ready for use.

By default the Web Meetings WebApp plugin is not activated for all users. Every user can configure it by
himself in the WebApp settings. However you can change this by setting:

    kopano-meetings/plugin/enable='True'

In the current configuration there is no turnserver configured, so Web Meetings will only work between
users within networks, where direct connections are allowed.

Kopano can provide a turnserver. To configure it set the following ucr variables:

    kopano-meetings/plugin/turn_use_kopano_service='True'
    kopano-meetings/plugin/turn_auth_user='[user provided by Kopano]'
    kopano-meetings/plugin/turn_auth_password='[password provided by Kopano]'

Access to Kopanos Turn service can be requested at: 
https://portal.kopano.com/content/turn-server-access-request

Another possibility is to setup your own turnserver. In such a case we recommend to user the 
coturn TURN Servers.

To configure Kopano Web Meetings using your own turnserver please set the following ucr variables:

    kopano-meetings/spreed/configSpreedTurn=True
    kopano-meetings/spreed/stunURIs
    kopano-meetings/spreed/turnURIs
    kopano-meetings/spreed/turnSecret

Further information can be found here wiki.z-hub.io.

moppert.de.             258235  IN      NS      b1.wpns.hosteurope.de.
moppert.de.             258235  IN      NS      b1.wsns.hosteurope.de.
moppert.de.             85435   IN      MX      10 mail.moppert.de.
moppert.de.             85435   IN      MX      50 mx0.moppert.de.
moppert.de.             85435   IN      TXT     "v=spf1 ip4:188.68.41.75 ip4:80.237.138.5 ip4:5.252.227.0 ~all"
moppert.de.             1595    IN      SOA     b1.wpns.hosteurope.de. hostmaster.moppert.de. 2020011309 16384 2048 1048576 2560
moppert.de.             85435   IN      A       80.237.132.79
box.moppert.de.         86116   IN      A       188.68.41.75
candy.moppert.de.       86216   IN      A       188.68.41.75
familie.moppert.de.     86400   IN      A       188.68.41.75
ftp.moppert.de.         86400   IN      A       80.237.132.79
ftp.moppert.de.         86400   IN      AAAA    2a01:488:42:1000:50ed:844f:c6:3e82
kiefer.moppert.de.      86400   IN      A       188.68.41.75
mail.moppert.de.        85435   IN      A       188.68.41.75
mx0.moppert.de.         85435   IN      A       80.237.138.5
wiki.moppert.de.        86400   IN      A       188.68.41.75
www.moppert.de.         107     IN      A       5.252.227.0

fliesenwolff.de.        259200  IN      NS      ns1.hans.hosteurope.de.
fliesenwolff.de.        259200  IN      NS      ns2.hans.hosteurope.de.
fliesenwolff.de.        86400   IN      MX      50 mx0.fliesenwolff.de.
fliesenwolff.de.        86400   IN      TXT     "google-site-verification=ZMTLaVEQxF04qYuiwbCqC_8sIAklpEbVQuZikv4yMvI"
fliesenwolff.de.        2560    IN      SOA     ns1.hans.hosteurope.de. hostmaster.fliesenwolff.de. 2018020819 16384 2048 1048576 2560
fliesenwolff.de.        86400   IN      A       80.237.133.55
fliesenwolff.de.        86400   IN      AAAA    2a01:488:42:1000:50ed:8537:ffb0:e8a5
ftp.fliesenwolff.de.    86400   IN      A       80.237.133.55
ftp.fliesenwolff.de.    86400   IN      AAAA    2a01:488:42:1000:50ed:8537:ffb0:e8a5
mail.fliesenwolff.de.   86400   IN      A       80.237.133.55
mail.fliesenwolff.de.   86400   IN      AAAA    2a01:488:42:1000:50ed:8537:ffb0:e8a5
mailout.fliesenwolff.de. 86400  IN      A       80.237.133.55
mailout.fliesenwolff.de. 86400  IN      AAAA    2a01:488:42:1000:50ed:8537:ffb0:e8a5
mx0.fliesenwolff.de.    86400   IN      A       80.237.138.5
www.fliesenwolff.de.    86400   IN      TXT     "google-site-verification=ZMTLaVEQxF04qYuiwbCqC_8sIAklpEbVQuZikv4yMvI"
www.fliesenwolff.de.    86400   IN      A       80.237.133.55
www.fliesenwolff.de.    86400   IN      AAAA    2a01:488:42:1000:50ed:8537:ffb0:e8a5

siehe auch:
https://help.univention.com/t/how-to-kopano-ucs-4-4-latest-install-dkim-support/11725/3
https://www.cubewerk.de/2017/12/04/spf-und-dkim-mit-univention-ucs-server/
https://kofler.info/dkim-konfiguration-fuer-postfix/