When terminated from a job what information about the termination may the employer reveal?

First of all, you need to have proof that your former employers actually communicated with one another.  Even if you do, generally there is no law against a former employer for a negative response to a prospective employer's inquiry.  Legally, an employer enjoys a "qualified privilege" for answers to pre-employment inquiries. This is so that companies will be free to answer those questions honestly without fear of a lawsuit. A former employee can only sue for willful and/or reckless remarks; that is for things that are completely and/or grossly untrue.  Also, even without the privilege certain statements are legally allowed. Statements of fact aren't actionable; so saying that they would not re-hire you can't be defamatory because they can prove it's true.  Additionally, statements of opinion aren't a basis for a lawsuit. For example, if your former employer said, "X uses drugs" that is a statement of fact that may be actionable; saying "I think X is the worst worker I've ever supervised" is a statement of opinion that may be hurtful and unfair, but is not actionable.  Bottom line, in order to sue for defamation, the information must be a false statement of fact.  

In any event, it's often very hard to prove what is being said about you in these situations. Without more details it's hard to say.  If you think that your previous employer has defamed you, you should consult with an employment law attorney in your area.