How do you stop a dog from pooping?

Well, you should have included more info (i.e. age, amount of time you let him out, when you go on walks, etc.), but my guess is its probably old enough to know how to go to the bathroom outside and I'm sure you take him/her out at least every now and then for a good walk, am I right? Well, first off, you should take your dog out for a nice little walk around the block once in awhile, as he/she may be pooping as a sign of a beg to go out. If that doesn't help, you should carry a squirt bottle of water know, your dog isn't some cat, but just spray it when it goes poop inside the house. This is actually a pretty logical technique, as it tells your dog no, without penetrating (most techniques involve hitting, making your dog fearful, and potentially abused) the trust of the two of you. When you two go on walks you should praise him/her when he/she poops on the grass, stating the differences between going poop inside and outside. That sense of rule in the last sentence, is proven because as you anger when your dog poops inside, he/she will not understand what they did, and may believe they aren't aloud to poop, but praising your dog when it poops outsidewould teach them they can still go do their thing, but OUTSIDE. Hope this helps.