Network IT Help: How to check available ports internally?

Hi everyone, I have a project coming soon to migrate these Aerohive AP's from our Controller here and migrate them to a cloud based manager. Now in order for this to work I need to make sure that port 12220 is open from the inside and will be able to communicate online. Does anyone know of a on site port tester so that I may check if its open or not? Also, I think it would help for future use as well.