Who can come on your property if you have a no trespass sign posted?

A 'No Trespassing" sign is not a universal ban. Anyone who has lawful business to conduct on your property (e.g.: utility meter readers - process servers - any governmental employee who have the authority to enter to conduct their business - emergency services personnel - US Mail delivery persons - etc.) Under normal circumstances ONLY door-to-door solicitors and other 'casual' visitors can be banned.