Most routers have built-in firewalls to protect your local network from threats and malicious attacks, but they're often disabled by default. You can turn them on by logging into your router's online user account. Find the security settings and activate the firewall.
For better security, make sure to use a WAP2 password. This is a custom password that you can require for every device trying to connect to your home network. Experts recommend using a password that is difficult to associate with you. An alphanumeric password is also ideal.