Barking at outside 'threats' please help!!

Sorry if this has already been done to death, if this has already been covered elsewhere please point me in the right direction!

Since moving (bout 6months ago now) my dog has gotten progresively worse with barking at people outside. Anyone that walks past our front door or lounge window sets him off with at least a growl, more often full scale barking and will keep doing it, and even then turn and bark at me until I have sent him to his bed. I guess this prob isn't the right way to react to it so how can I discourage this, or make him feel like I have noticed and am not bothered by the 'threat'? I feel mean makin him sit out coz I know he is just doing his doggy duty but I really want to stop it getting even worse or before we get conplaints!

Staffies aren't actually a guarding breed, so barking at people passing isn't an inherited trait, though the terrier side can make them a little excessive. Has he ever had a negative experience with passers by/visitors? How often is he walked? And how old?

No, he is always very pleased to see any visitors regardless of whether he knows them or not. I wouldnt describe him as a nervous dog either. Gets lots of exercise, and has things to keep him occupied at home. Tends to be worse if the people are talking or making a noise. Has started to do it at night as well more recently, we live in a ground floor flat with communal hall so there are people in and out loads. Though the ones that walk past the hall bother him less than people he can hear and sometimes see (if he stands in the arm of the sofa) outside the window.

When you say lots of exercise, how often are we talking and what sort of exercise? It may well be territorial, and short of training a "quiet" command and distracting you can't train the instinct out of him. I lived in a flat with Bug in Central Bristol initially and she would go off on one anytime anyone walked past, especially men, but is a rescue with major stranger issues so hers was down to fear. May be an alarm bark, but that would say fear to me.

Is he an obsessive/compulsive sort of dog at all? Does he tend to repeat behaviours? Most dogs thrive on routine, but some crave it more than others and many behaviours can become ritualistic.