What are the methods by which an attacker can distinguish between DROP on IPtables and a Nullroute or non-allocated IP?

Let’s say we have a server set up with set to:

iptables -P INPUT DROP

Without any other rules on the input chain.

Ignoring accessibility issues outside of physical server access, what are the methods that an external … Continue reading What are the methods by which an attacker can distinguish between DROP on IPtables and a Nullroute or non-allocated IP?