IK Degree of Freedom

In Blender 3D: Noob to Pro, i saw something here about IK that said on an IK Armature, you can set a DOF or something so a character’s arm will not bend backwords or something when I am doing IK. Where on Blender can I find this? or if it is not there, what else would I use for this? thanks for your time

Never mind, I found it… sorry