Configuring Federation Sharing
Federated Cloud Sharing is now managed by the Federation app (9.0+), and is now called Federation sharing. When you enable the Federation app you can easily and securely link file shares between Nextcloud servers, in effect creating a cloud of Nextclouds.
Configuring trusted Nextcloud servers
You may create a list of trusted Nextcloud servers for Federation sharing. This allows your linked Nextcloud servers to share user directories, and to auto-fill user names in share dialogs.
You may also enter Nextcloud server URLs in the Add Nextcloud Server field.
A red light means the connection failed. The yellow light indicates a successful connection, with no user names exchanged. The green light indicates a successful connection with user names exchanged.
The prerequisiste for a green status is that the trusted servers were maintained
in both interacting Nextcloud servers.
Additionally occ federation:sync-addressbooks
must have been executed (part of
cron job list). The delay to execute the cron is based on local configuration of
the cron frequency.

Configuration tips
The Sharing section on your Admin page allows you to control how your users manage federated cloud shares:
Check
Enforce password protection
to require passwords on link shares.Check
Set default expiration date
to require an expiration date on link shares.Check
Allow public uploads
to allow two-way file sharing.If you encounter timeouts for downloading or uploading large files, you can use the option
davstorage.request_timeout
in yourconfig.php
to increase the timeout. The default value is 30 seconds.
Your Apache Web server must have mod_rewrite
enabled, and you must have
trusted_domains
correctly configured in config.php
to allow external
connections (see Installation wizard). Consider also
enabling SSL to encrypt all traffic between your servers .
Your Nextcloud server creates the share link from the URL that you used to log
into the server, so make sure that you log into your server using a URL that is
accessible to your users. For example, if you log in via its LAN IP address,
such as http://192.168.10.50
, then your share URL will be something like
http://192.168.10.50/nextcloud/index.php/s/jWfCfTVztGlWTJe
, which is not
accessible outside of your LAN. This also applies to using the server name; for
access outside of your LAN you need to use a fully-qualified domain name such as
http://myserver.example.com
, rather than http://myserver
.