Recent versions of Barman allow you to do WAL archiving without using an rsync/ssh-based archive_command. Instead, the backup server uses streaming replication via the standard pg_receivexlog command to build up a WAL archive. The big new feature in Barman 2.0 is that it can take base backups using pg_basebackup, rather than rsync. This means that it can be used without SSH access between servers (only replication connections to Postgres on port 5432).