Many dogs automatically bark when they hear a knocking or a doorbell at your front door. However, some dogs need to be trained to perform this act of alerting their owners of someone at the door. Though some dogs are territorial and want to know what's happening at your front door every moment of every day, others may feel this is your job because you are the leader of the pack.
Training your puppy to bark when there's someone at your front door can benefit many dog owners, from individuals with hearing loss to those who want to ensure the safety and security of their home. Alerting you when there is someone at your door can be a task you teach your puppy, so for his entire life, this task becomes his responsibility and in essence, his job. This helps dog owners in high-rise buildings with buzzers or doorbells or even out in the country with a simple knock on the door.
Starting this training will require you to know what your puppy is interested in doing from the start. If he barks at your door already when he hears the doorbell or not, he is likely to continue this behavior. If he doesn't bark now, it is something you will need to train specifically. If there are other things your dog is interested in barking at, such as noises around the house, you can redirect these noises to specifically the noise at your door. You can also teach your puppy to speak when he hears a noise. This will condition him to automatically speak when he hears that noise coming from the other side of the door. You may need some help creating noise at your front door, but ultimately if you teach him to bark at the sound of a doorbell or knock from inside your home, he should associate that with the noise he hears when there's someone at your door as well.
Other than the distraction and noise coming from your door, you will want to train this task free of distractions. You can train different commands or simply train your dog to react to noises. You may want to have some tasty treats on hand, as you do with all of his training, to reward him for his responsiveness.