Firewall settings

Hi,

I just got a new macbook pro and I came across the Firewall setting in preferences which was OFF. I'm assuming that this is the apple OS default setting. But why would this be, surely the default should be ON?

Does anyone know about the OS firewall and it's strength? Do you all have it switched ON?

 

Thanks for your reply atlanticza, makes sense to me now having read the linked article.