IP addresses are stock you sell, provision and reclaim. What an IPAM records, how it differs from DNS and DHCP, the five ways an IP spreadsheet fails, and a checklist for VPS, dedicated and colo hosts.
Ilinca Bostan12 min readIPAM (IP address management) is the system that keeps one authoritative record of every IP block and address you hold: how your supernets are split into subnets, which VLAN and gateway each subnet uses, and which device, service or customer holds each address now and held it before. For a hosting provider, IPAM is also stock control for something you sell.
Enterprise IT uses IPAM to keep a network tidy. Hosts need more, because an address is a product line: sold as an add-on, handed out when an order provisions, taken back when a service ends, and looked up when an abuse report arrives. Below: what an IPAM tracks, how it differs from DNS and DHCP, when a spreadsheet stops being enough, and what to check if you sell VPS, dedicated servers or colocation.
Every IPAM holds the same six kinds of record.
Utilisation falls out of the assignments, and tells you to buy or reclaim space before an order fails.
No. The three are often sold together as DDI — DNS, DHCP and IPAM — but each does a different job.
DDI suites put the three under one console so leases and records update the register automatically — valuable in an office full of laptops. Hosting is different. Customer servers and VMs mostly get static addresses written into their configuration at provisioning, so the register, and its link to the customer who pays for each address, does most of the work.
A spreadsheet is a reasonable IPAM for one person and a couple of /24s. It breaks in predictable ways.
Double assignment. Two people see .45 as free and both use it. Nothing in a spreadsheet enforces one holder per address, so the first sign is two customers with intermittent outages and an address conflict nobody suspects for an hour.
Addresses that never come back. A service is terminated in billing and its row still says “assigned”. A few years of churn later you hold a /24 that is a quarter dead while you shop for more space. That is real money: one marketplace’s tally of priced IPv4 transfers in the first half of 2026 put the average at $20.04 per address, about $5,130 for a /24.
The abuse report you cannot answer. A complaint names traffic from 203.0.113.45 at 14:10 on 3 March. The sheet tells you who has that address today. If it changed hands since, you name the wrong customer or nobody — and the same question arrives from law enforcement.
Registry records that drift. RIPE NCC policy says all assignments must be registered in the RIPE Database and the data kept correct at all times; ARIN’s policy manual requires IPv4 reassignments of a /29 or larger to be registered and visible within seven days. A sheet updated when somebody remembers cannot meet either. Registry rules and lawful-request obligations differ by region; this is not legal advice.
The wrong datacenter. With two sites, a free address is only useful where its block is routed. A sheet that lists “free” without a location invites somebody to give a Frankfurt address to a server in Amsterdam.
The moment to move is one of three: a second person assigning addresses, provisioning that should pick addresses without a human, or a second location.
IPv4 is per-address inventory. The RIPE NCC made its last /22 allocation on 25 November 2019; new members can only join a waiting list for a single /24, and everyone else buys on the transfer market. An IPAM should track individual IPv4 addresses, show utilisation per block, and make reclaiming idle space routine.
IPv6 is per-prefix inventory. Nobody runs out of IPv6, so you track which prefix went where, not individual addresses. A /64 per server or VM is the usual unit, and customers who route their own subnets get more — RIPE-690, the operators’ best practice for end-user assignments, strongly discourages anything longer than a /56. Allocate the prefix to the service and do not create a record per address inside it.
Prefix sizes and whether to charge for IPv6 are covered in IPv6 allocation and billing for hosting providers. The IPAM point is simpler: keep both families in the same register, against the same services.
General-purpose IPAM is built around devices and networks. A host’s IPAM must also be built around orders and customers.
The third column is the question that separates a real answer from a brochure.
| Capability | Why it matters to a host | Ask the vendor |
|---|---|---|
| Subnet tree for IPv4 and IPv6 | You carve customer blocks from larger allocations | Can a /24 be split to /29s and merged back once they are free? |
| VLAN and location on every block | An address is only useful where it is routed | Will it refuse a block for equipment at another site? |
| One holder per address | Prevents double assignment | Is uniqueness enforced by the database, or only by the screen? |
| Link to service and customer | Abuse, billing and audits start from an address | Can I get from an IP to the paying customer in one step? |
| Allocate on order | Removes the manual step where duplicates enter | Is free space checked before hardware is committed? |
| Release on termination | Stops dead assignments piling up | Does termination free addresses with no staff action, and what stays attached? |
| Holds with a reason | Keeps blocklisted or infrastructure space out of rotation | Can I park an address without deleting it, and see why? |
| Allocation history | Answers “who had this address on that date” | Is history kept after the service or customer is deleted? |
| Low-space warnings | Buy or reclaim before orders fail | Does it warn me per location before a pool runs dry? |
| Priced IP add-ons | Invoice and allocation must agree | Does buying an extra-IP option allocate the addresses? |
DCIM — datacenter infrastructure management — tracks the physical estate: racks, devices, power, ports and cabling. IPAM tracks the logical estate. They meet at the device an address is assigned to, the switch port and VLAN that carry it, and the location both belong to. As separate products, each join is an integration you maintain; in one schema, an abuse report goes from address to service to rack in one lookup. The physical side is covered in DCIM software for hosting and colocation.
FluxBilling is billing, DCIM and provisioning for hosting providers, and IPAM is part of every plan. What it does today, per the IPAM documentation:
The limits, plainly. Freed addresses go straight back to Available; there is no automatic cool-down, so to rest released space, mark it unavailable with a reason and clear the hold later. There is no CSV import on the IPAM page: you register your blocks by CIDR — a handful of entries for most hosts — and address records build up as services provision or as you allocate. And it is not a DDI suite: DNS and DHCP servers managed from one console across a corporate network are a different category of product. The IPAM feature page shows the allocation engine in more detail.
IPAM, DCIM and billing are on every FluxBilling plan from €4.95 a month ($5.95 for US accounts) — see pricing. Subscriptions carry a 14-day refund, or try the live demo first.
IPAM, or IP address management, is the planning and record-keeping of an organisation’s IP address space: which blocks it holds, how they are subnetted, and which device or customer uses each address. It can live in a spreadsheet, a dedicated tool or a larger platform.
No. DHCP hands addresses to hosts automatically from configured ranges; IPAM is the register of which ranges exist and who holds what. DDI suites connect the two, but you can run IPAM with no DHCP at all, which is common for statically addressed servers.
Yes, while one person assigns addresses from a couple of blocks at one site. It stops working when two people assign at once, when provisioning should pick addresses automatically, or when you need to know who held an address on a past date.
DCIM manages physical infrastructure: racks, devices, power and cabling. IPAM manages logical addressing: subnets, VLANs and IP addresses. Hosting providers need both, and they work best sharing records, because addresses are assigned to the devices DCIM tracks.
Yes. IPAM comes as hosted software, as self-hosted tools, and as a module inside hosting platforms. FluxBilling is the last kind: managed, with IPAM on every plan, and self-hosting on the Business plan for a one-time fee.
You will not run out of IPv6, which is exactly why its allocation goes undocumented. Meanwhile IPv4 leaks onto dead services. Both are billing problems, not just network ones.
Looking for an EasyDCIM alternative? FluxBilling includes full DCIM with rack management, IPAM, inventory tracking, and network monitoring at no extra cost.
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