It was popular, but not universally popular. Hence there was a civil war between the Austrian Nazis and the Austrofascists. There was the largest support in the rural provinces. Dolfuss remarked that he could win the civil war if he could just put a wall around Carinthia. The anschluss has been referred to as "the revolt of the provinces against Vienna."
Modern Austrians insists that they were annexed against their will and had absolutely nothing to do with it.