My puppy freaks out whenever anyone approaches the door. I tend to keep the front door open, both because I like the sunlight in my home and because my dog whines when I close it, but I do close it if I notice him barking or jumping on the glass. Unfortunately I live near kids and various people, and it doesn't take much to set my puppy off. Although just to clarify, he's not violent. If a stranger did enter the house he would probably bark, sniff them, then bark some more until get got comfortable.

Today he barked at the mailman. Worse still, he managed to open the door a little. He didn't get out, and I was there to hold him back, but the mailman was obviously unhappy. The neighbors probably hate me and my dog for the same reason. It makes me not want to talk to anyone in my neighborhood.

I thought he would age out of being reactive like that, and he's only around a year and a half old at this point. But he's fifty pounds, and I can't have him scaring anyone. I tried spritzing him with a water bottle a few times, but that doesn't work as well as it could. I'm also concerned that will lead him to believe all barking is bad, which I fear may cause him to become anxious and aggressive later on. I don't know what to do, and I feel like I'm failing every day.

Also he's leash reactive, but I'm working on that with a trainer. I got a new collar that's keeping him from being reactive on walks. I could have him wear it in the house, but that would probably be uncomfortable at best, and dangerous at worst (it's one of those pronged collars).

EDIT: I've been getting comments saying that punishing my puppy's behavior would be bad, and just so we're clear, I agree. I don't even like the pronged collar all that much, but supposedly it doesn't hurt him, and my trainer swears by it. I prioritize making him comfortable over making him quiet.