What a fair IPv4 lease agreement should contain

An IPv4 lease is only as good as the agreement behind it. This checklist walks through the clauses a fair contract should contain, what each should say and the warning signs to look for, whether you are leasing addresses in or leasing them out. It is general guidance rather than legal advice, so have your own lawyer review any agreement before you sign.

Term, renewal, notice and termination

Start with the basics: vague definitions leave room for disputes later.

• Exact resources. List each prefix in CIDR notation and the registry that holds it. “A /24” is not enough.
• Start date. Tie it to when the addresses are actually usable, such as when the ROA and route object are live, not to the signing date.
• Minimum term. State it plainly, along with whether fees remain due for the whole term if the lessee leaves early.
• Renewal. If the lease renews automatically, say for how long and on what terms. A fair agreement either fixes the renewal price or requires written notice of any change well before the renewal date, so the lessee can decline.

Notice periods should be long enough to renumber and, ideally, the same for both parties. If the lessor can end the lease at short notice while the lessee is locked into a long minimum term, the balance is wrong.

For termination, look for:

• Termination for convenience: who may use it, from when, and with how much notice.
• Termination for cause: what counts as a material breach, and a cure period before termination takes effect, except in serious abuse cases.
• A wind-down window: a defined period after termination during which routing continues, so services can move in an orderly way.
• Registry objects at the end: a commitment to withdraw the ROA and route object on a stated date, not earlier.

Abuse handling and acceptable use

Abuse handling is where a lease is tested hardest, so this part deserves detail. A fair agreement sets out:

1. An acceptable use policy describing what the addresses may and may not be used for, in specific terms.
2. The abuse contact shown in the RIPE Database for the range, and who actually handles reports.
3. Response times for acknowledging and resolving reports, ideally graded by severity.
4. An escalation path before suspension: notice, deadline, then action.
5. Emergency suspension rights for serious cases, such as an active attack, with the conditions spelled out.

Lessees should resist clauses that allow suspension at the lessor’s sole discretion, with no notice or explanation. Lessors should insist on prompt, documented abuse handling. Both interests can sit comfortably in the same clause.

LOA scope, ROA, route objects and rDNS

The Letter of Authorisation (LOA) tells upstreams that the lessee may announce the prefix. Its scope should match the deal exactly:

• Which prefix or prefixes, and whether more-specifics may be announced.
• Which origin ASN is authorised.
• A validity period ending no later than the lease.
• When and how it can be revoked.

Registry work needs equally clear ownership. The contract should state who creates and maintains the ROA, the route object in the IRR and the reverse DNS delegation, how quickly changes are made, and how requests are submitted. If the lessee wants to change its origin ASN or add an upstream, there should be a defined process and turnaround, not an open-ended “on request”.

It is also worth agreeing how the assignment appears in the RIPE Database, because that decides where abuse reports and queries about the range are sent.

Reputation at handover and on return

Both sides have a stake in the block’s reputation, so the contract should deal with it at both ends of the lease.

At the start, the lessor should confirm that the block is free of listings on major blacklists, such as Spamhaus, and that it knows of no routing disputes over it. A fair contract lets the lessee check this before the term begins and reject or swap a block that fails.

At the end, the lessee should return the block in a comparable state. Good clauses define:

• what “clean” means and which blacklists are checked;
• who pays for delisting when a listing arose during the lease;
• how long the lessee has to resolve listings after return;
• how a listing that appears shortly after handover is attributed.

Without these points, disputes over a late listing are hard to settle fairly.

Liability, warranties and the remaining clauses

The final group of clauses decides who carries the risk when something goes wrong.

• Lessor warranties: that it is the registered holder or is authorised to lease the space, and that the arrangement complies with registry policy.
• Liability caps: a cap is normal, but read the exclusions. Make sure the lessee’s losses from a wrongful early termination are not excluded entirely.
• Indemnities: the lessee usually indemnifies the lessor for misuse of the addresses. Keep this limited to the lessee’s own conduct and that of its customers.
• Registry changes: what happens if a change in RIPE NCC policy or a registry decision affects the lease.
• Fees and payment: currency, VAT treatment, invoicing frequency and any deposit, including when it is returned.
• Assignment and change of control: whether either party can transfer the contract, for example after an acquisition.
• Governing law and jurisdiction: where disputes will be heard.

How TACS can help

As a RIPE NCC member, we draft our agreements with both sides of the lease in mind and are happy to explain any clause before you sign. Whether you want to lease IPv4 or lease out your IPv4, we can walk you through the terms, and an IP security audit can confirm a block’s reputation before it changes hands.