Leonberger Question

I have a male leonberger mix, and he is extremely calm, friendly, tolerant. Like most dogs, he takes his cues from me, so friendly strangers get a tail wag, as do children (even a few who have pulled his tail or tried to ride him) but "unfriendly" strangers, or those at the door uninvited (UPS guy, aggressive salespeople) get a resounding bark/growl as he assumes a protective stance infront of me.

Any dog, no matter the breed, will protect home and family or as they see it, pack and territory. Even the friendliest dog that usually would lick your face off rather then bite will still get protective if they sense something is wrong or an outsider is upsetting their pack.