What Is IPv4 Dark Space — and Why It Matters
Every IPv4 address is allocated. Most of them are quiet. Dark space is the dormant part of the internet — and it is a market signal.
The internet is full — on paper
All 4.3 billion IPv4 addresses are allocated to organisations. But allocation is not the same as usage: a huge share of registered address space simply sits unused, quietly holding a place in the registry for years.
That quiet space has a name: dark space. It is the portion of the IPv4 address space that is registered, announced at some point, and now responds to nothing — no web server, no DNS, no router answering on common ports.
Why it matters
IPv4 is scarce and expensive. A single address trades in the tens of dollars on the transfer market, so a dormant /24 block is real money standing still — and a /16 is a fortune. For brokers, leasing desks and security teams, knowing which blocks are dark is the difference between finding inventory and hunting blind.
Dark space is also risk: unused space gets hijacked, abused for spam or absorbed into botnets before anyone notices. A map of silence is a map of risk — and of opportunity.
How to observe it
You cannot read the registry alone — registration dates and routing announcements only tell half the story. You need measurement: passive, rate-limited probing that asks each address "are you there?" and records the silence. That is exactly what IPDORM does, continuously, across all five RIRs.