We saw busted PMTUD on a customer's network trying to get to us via a misconfigured network link. It's a bad problem to debug. None of us knew what PMTUD was, o

We saw busted PMTUD on a customer's network trying to get to us via a misconfigured network link. It's a bad problem to debug. None of us knew what PMTUD was, or that TCP can require ICMP to work, until that day.