glIndexPointer is available only if the GL version is 1.1 or greater.The color index array is initially disabled, and it isn't accessed when glArrayElement, glDrawElements, or glDrawArrays is called.
Execution of glIndexPointer is not allowed between glBegin and the corresponding glEnd, but an error may or may not be generated. If an error is not generated, the operation is undefined.
glIndexPointer is typically implemented on the client side.
Since the color index array parameters are client-side state, they are not saved or restored by glPushAttrib and glPopAttrib. Use glPushClientAttrib and glPopClientAttrib instead.