I have a Boxer pup of 7 month old, he is too friendly, I want to train him to be a guard, he does not bark when door bell rings so what can I do to make him aggressive.
First off, just my personal opinion, but I would try steer clear of training your dog to be thoroughly aggressive. There can be a difference between guarding and being aggressive, I would go for training your Boxer onto alerting behaviors, instead of aggressive ones.
If you want your dog to guard in the sense that it barks when someone approaches your property, train him to do it with you and friends first. Have someone with the dog, and another person approach the property. If the dog automatically starts barking, praise it and reinforce the behavior. If not, encourage it to by saying "speak" and getting it worked up, play with it, etc. Once he starts barking, again, reinforce the behavior by praising him and giving him treats. Keep working like this, with different people and situations.
You can use the same basic training technique to get your dog to guard property, items, areas, etc.
If you have more specific behaviors desired from your dog, let us know, and we'll help where we can
I agree with Caroline. If you have a boxer, you already have a dog that people are going to be leery of. If they know the dog is in your house, they won't come in uninvited. Does't matter that your dog might show a thief where all the good stuff is -- the thief doesn't know that. All he sees is a big dog with wicked teeth.
If you insist on an aggressive dog, make sure you get an authority to help you train him. Otherwise, you may find yourself with an empty collar when your dog bites someone inappropriately.
