Is it an absolute truth and we can not know absolute truths?

This rhetorical question or some variation is common response a receive in a debate to sort of increase the fog index and divert form the debate at hand. What is the name for this fallacy?

It is one of those questions that people who think they "gotcha" like to ask. "Oh, we can't be certain about anything? Are you certain about that?" Clearly, if one is rejecting the idea of certainty, truth, or any other concept, when they make a statement such as "there is no..." they are not claiming certainly, truth, or whatever.

The person who asks that question is trying to set the other person up for a self-refuting statement (a fallacy). One could argue that the question itself reflect a self-refutation, but clearly those who ask this question are being ironic and attempting to point out an illogical position. Just to reiterate, the position is ONLY illogical if someone were to claim certainty that there is no certainty, or similar self-refutation.