Then again, I did read (parts of) the RFC from &#x27;81, some paper (from Morris iirc) about predicting the ISN from &#x27;85, lots of research in the 90&#x27;s and early 00&#x27;s regarding predictions and preventing it... but nothing actually just guessed the number, and people seemed to agree that &quot;if the ISN is unpredictable then yeah it&#x27;s secure right?&quot; That&#x27;s why I considered this a new thing.