When trying to analyze an animal’s body language, each signal must be taken in context. Other body language signals should be analyzed as well to form as complete as possible view of the animal’s intent or emotional state. You can generally characterize signs in 3 categories: go, stop and yield.
Dogs can put their ears forward for many reasons. Generally, this means that they are alert or focused on something. They could be focused on a squirrel that they want to chase or a person to whom they may be aggressive. It is best to interpret this as a yield signal which means that you should try to analyze the situation and look at the other body language signals to determine the best next steps.