Make MariaDB listen on all interfaces (insecure option)

Check ports:

$ ss -ntl #3306

Check configuration:

$ mysqld --help --verbose | head
$ cat /etc/mysql/my.cnf

Edit configuration:

$ sudo vim /etc/mysql/mariadb.conf.d/50-server.cnf

Set:

#bind-address
skip-bind-address

Restart service:

$ sudo systemctl restart mariadb

Check again:

$ ss -ntl