Make sure your property is properly fenced
Dachshunds are natural explorers. There always seems to be something of interest on the other side of the fence and they'll try to get to it at al costs. If you allow your pet outside unattended at any time, you have to make sure your fencing is secure.
Look at your fencing from your dachshund's point of view. This means a low-level examination for openings and week points that could quickly be exploited. If your dachshund spends any time outside unattended, they can quickly dig underneath a fence if they think they can get to the other side. This usually happens if the fence has a small gap at the bottom that the dog can push against. Once a dog has learned they can dig under the fence they'll be more likely to try it in the future.
Dachshunds can't jump normal residential fences, but I have seen some that can climb fences. Most won't climb, but if you happen to have a climber on your hands, you'll have to be very careful leaving them alone in the yard, especially if you have a chain link fence.