Scarce Numbers: The Address Cost Hiding Quietly in Your Hosting Renewal

The line item is easy to miss. Somewhere between the managed backup tier and the support uplift sits a charge for additional IPv4 addresses, expressed in pounds per month per address. It was not there three renewals ago. It is there now, and in a growing number of UK contracts it will be larger next year.

The reason is straightforward, if rarely explained to customers: the internet's original addressing scheme has been exhausted for years, and the addresses a business depends on are now a traded commodity with a market price.

A Twenty-Year-Old Shortage Arrives on the Invoice

IPv4 provides roughly 4.3 billion addresses — ample in 1981, insufficient for a world of phones, sensors, containers and load balancers. The regional internet registries handed out their final free blocks over a period ending in 2019, when RIPE NCC, the registry covering Europe and the UK, exhausted its remaining pool.

Since then, addresses have moved only by transfer: one organisation selling or releasing a block, another buying it, with the transaction recorded in a public registry. Broker estimates put the price per address many times higher than it was a decade ago, and the market is thin and lumpy. A /24 — 256 addresses — is now a meaningful capital purchase for a small provider, not a rounding error.

That pressure does not vanish. It is passed on, and the passing-on is usually designed to be inconspicuous.

How the Scarcity Reaches a UK Invoice

In practice, the cost surfaces in five forms:

• Per-address monthly fees. Each public address beyond a small default allocation is charged at a recurring rate, sometimes with a minimum term.
• Bundled allowances. A contract includes, say, five addresses and sells more at a premium — often without stating the increment or the ceiling.
• Assignment or setup charges. A one-off fee for "address provisioning" when a workload is created, particularly for workloads requiring several static addresses for outbound traffic.
• Reclamation and legacy language. Providers reviewing "unused" or "historic" allocations may ask customers to justify holdings, or may restructure terms around them.
• Migration constraints. Moving between providers can mean surrendering addresses, because they are registered to the provider rather than to you.

That final point matters more than the others, and it is not primarily a financial matter.

The Sovereignty Wrinkle

Internet addresses are registered to a legal entity: typically the hosting provider's local internet registry account. The customer rents the use of them. Change supplier and, in most cases, the addresses stay behind, which means DNS changes, mail reputation resets, allow-list updates with partners and a period of dual-running that nobody budgeted for.

There is a geographic dimension too. Geolocation databases infer location from registry records, and that inference drives content localisation, fraud scoring, geo-blocking and streaming rights checks. An address block registered to an overseas parent company may resolve to Amsterdam, Frankfurt or further afield even when the servers sit in Manchester. UK businesses that advertise UK-based hosting should verify that the addresses in use are registered to a UK entity and geolocate accordingly — and should say so in the contract, not assume it.

Recycled addresses bring a second risk. A block previously used by a sender of bulk email carries a reputation with it. New tenants of such addresses can spend weeks repairing deliverability they never damaged.

What IPv6 Actually Changes — and What It Does Not

IPv6 removes the scarcity by providing a practically inexhaustible address space, and UK adoption is now substantial: a large and rising share of traffic to major UK consumer platforms is delivered over IPv6, reflecting the efforts of the large ISPs. For hosting, the practical position is dual-stack — IPv6 alongside IPv4 — rather than replacement.

The reasons are operational. Legacy line-of-business applications assume IPv4. Some third-party integrations, older VPN concentrators, internal monitoring tools and mail reputation systems were never configured for IPv6 and may fail silently when presented with it. Firewall rules written years ago reference four-part addresses only. Nothing here is insurmountable; all of it requires planning.

Two misconceptions are worth retiring. Network address translation is not a security control — it is a workaround for scarcity, and treating it as a firewall has caused more than one authentication and logging problem. And IPv6 is not simply "more addresses": it changes how devices are numbered, how logs are read and how access rules are expressed.

Clauses Worth Reading Twice

Before signing or renewing in 2026, UK buyers should be able to answer the following from the contract alone:

1. How many public IPv4 addresses are included, and at what recurring cost beyond that allowance?
2. Are the addresses registered to a UK entity, and can that be evidenced in writing?
3. On termination or migration, can addresses be transferred, for how long, and at what cost?
4. Is IPv6 available, dual-stack, at no additional charge, and is it supported in the provider's firewall and load-balancing products?
5. Are outbound addresses dedicated or shared, and for mail-sending workloads, is there a documented warm-up and reputation process?
6. Do any services — VPN endpoints, API gateways, partner integrations — require fixed addresses, and is that requirement priced?

Address Planning Belongs in Strategy

An address inventory is a small piece of documentation with disproportionate value. Record which workloads need static public addressing, which can sit behind shared egress, which require dual-stack, and which depend on geolocation accuracy. Revisit it whenever a service is added or a supplier changes.

The alternative is the position many UK businesses currently occupy: discovering, at renewal, that a resource they thought came free with the internet has become a metered utility — and that the meter is attached to a supplier relationship they cannot easily leave.