Rsync can run over SSH (most common) or as an rsync daemon.
Most backup jobs use command scripts and SSH keys; no dedicated rsync config file is required.
/etc/rsyncd.confExample module:
uid = nobody
gid = nogroup
use chroot = yes
max connections = 4
[backup]
path = /srv/rsync/backup
read only = false
hosts allow = 10.0.0.0/24
auth users = backupuser
secrets file = /etc/rsyncd.secrets
rsync --version
rsync --daemon --no-detach --config=/etc/rsyncd.conf
sudo ss -tulpn | grep :873