Alert barking and frustration barking come from different places in the dogs brain.

Frustration barking is when your puppy sees something and REALLY wants it. It's usually
combined with lunging at the end of the leash. That behavior is to be corrected/redirected.
Alert barking comes from fear and is usually accompanied by low body posture. Our dog
needs to be taught to look to you for an opinion on the situation rather than take it upon
himself to make the decision that something is a danger to him.
If you have an alert barking situation, bring your dog directly to the heel position
and wait for him to settle (look for changes in ear position, open mouth, relaxed down, tail
wag, etc.) and look up at you for direction. Try not to speak to the dog, just wait. Then
try a CHECK IT OUT and bring him toward whatever made him bark~if he is willing.

Its easier for the dog to be settled before you try to get him to go face his fears. If he doesn't want to go,
then just stand with him in a place where he's comfortable and wait for him to settle.

Please write any sort of barking behaviors in your online reports, along with where and when it happened