Hope one of these helps. Comes in a orange box and I seen it at our local hardware store the other day. The herb Pennyroyal is an ant deterrent. I am lucky enough to have an herb garden just outside my back door and have planted Pennyroyal as a border and have not had an ant problem since. I imagine that a pot of this plant sitting on a porch or steps would be just as effective.
Ant powder is nasty, nasty toxic stuff and best avoided.
Alternatively, have you considered a pet ant-eater. I had an ant problem the first year I moved into my new house. I haven't seen any in 5 years.