He is just barking and scratching at the door to get attention.
If this behavior hadn't been reinforced somehow, at some point, it wouldn't exist. All behavior depends on consequences. If the consequences are favorable to the dog, then the behavior will repeat. Now, barking is sometimes a self rewarding behavior. That is...that the dog enjoys hearing himself bark. LOL.
I'd practice inside first and work on the outside as a later exercise. If he is barking at visitors, yes, have them ignore him. But in addition, I would....in this case do something to interrupt the barking since that may be a payoff for him in and of itself. Has he learned any obedience basics? If you can get him to sit (you can teach him that at other times....when it's quiet, no distractions) when he's barking. When he is looking at you and sitting, he may well be quiet for a second or two, even if it's just to catch his breath. At that second while he is inbetween barks, use a marker word (I'll explain that in a minute) and reward with a yummy treat.
So, when a behavior is contingent on attention, yes, ignore completely. If a behavior is self rewarding and not only contingent on your attention or your guests, but because the dog gets enjoyment out of the act itself, then you need to distract or interrupt it, give an alternative behavior that he can be rewarded for. Keep the payoff of the barking fun from happening in the first place. You can put it on a cue. When he is able to stop when you interrupt him and he is getting very good at it....learning that when he stops for a couple seconds, good things happen, you can then start adding a cue, ("enough.") After quite some time, when you can tell that he's associating the word, "enough" with the stopping of the barking, you can try using the cue while he's barking to stop him. But at first, only use the word when it's connected with the quiet.
A marker word is like a clicker. It is used ONLY to mark a behavior...not to get the dogs attention, not as the reward, but as the bridge to the reward.
You say your marker word or use a clicker and give a treat immediately after, within 1 or 2 seconds, but not at the same exact time as the marker word. Repeat this over and over in different locations and contexts. Then you use your marker word at random times and if he looks expectant, like he's making the association that when he hears this, it means he's going to get a treat in a second, you know your dog is primed to the marker.
This makes for a very precise communication to the dog that the behavior he just did IS exactly what it is he's getting rewarded for.
So, in that one or two seconds of quiet, say your word or click the clicker. (I use "yesssss" for a marker word and I use a clicker sometimes too) Then treat. He will get the association between the quiet and the reward better this way. When we reward, we often get it to the dog too late and he associates the reward with the wrong behavior. This is the beauty of clicker training. It's very concise communication to the dog. It's based on classical conditioning....Pavlovian response.
So, in a broad way........teach your dog what behavior it is he's doing which is earning him attention and yummy treats. Teach your dog that the barking and exciteability is getting him nothing. It's getting no pats or looks from people, it's getting interrupted every time so that's no fun. But....when he's quiet and on all fours, he's getting treats, praise, pats. It won't take forever for him to figure out what behavior he wants to choose. He'll choose "right" if you set him up for it and be consistant. Everyone who interacts with him needs to be consistant.
Good luck. Lots of work, not easy, probably won't be perfect. I know....I have two yappy Chihuahuas along with my Dobe and another dog.