My 2 year old sweet, friendly, playful shih tzu really goes after anyone who comes to the door of our home. He'll also go after people he sees on a walk near our house. If I take him out to a park or downtown he is fine. I get it that he is either scared or being protective but what do I do? By going after them I mean he runs at them, barks, and will nip if he gets close enough. In 5 minutes he's fine but it scares me.
If this only happens at your house, it's defensive. He's trying to protect 'his' territory. If he attacks friends and family who come in the house, take him and lock him in a seperate room till he calms down, let him out and lock him back up if he does it again. Or have anybody who comes into your house give him treats. Key is, get him to know they're not a threat and ignore him when not exhibiting good behavior (jumping, etc.)
My; dogs: Blizzard and Max. cats: Frosty, Snickers, Crystal, Felix (black cat in pic), Sinder, Vince, Binx, Rei (tiny cat in pic). Birds: Ash (cockateil) Fitch & Sheila (Zebra finches)