Having worked in the HR arena for quite a while now, I have found that most companies do have restrictions, on who can do a reference, and what they can say. I will say that most places do advise dates of hire, and last title held. The End. I have been known in the past to "sigh" when a future employer asks about a poor employee, or just pause a lot. On the other hand, I have also told that employer to tell a former good employee that I wish them well and to keep in touch.