What an IPv4 lease contract should contain

A lease is only as good as its contract. Two leases at the same price can be very different things: one keeps your block stable for years, the other lets the lessor renumber you at the next renewal or charge per address when something is listed. These are the ten things to read before you sign, in roughly the order they cost people money. How a lease runs from the first message to live addresses is in how leasing IPv4 works.

1. Which block, exactly

The contract should name the prefix, the registry and the status of the block, not just "a /24". A named block can be checked before you sign (how to check a block); "a /24 from our pool" cannot.

2. What happens at renewal

The most important clause, and the one most often missing. Will you keep the same block when you renew, or may the lessor give you a different one? Renumbering a production network costs far more than any difference in price (what readdressing involves). Some lessors sell continuity as a paid extra; look for it in writing either way.

3. When the block can be taken back

Every lessor has some reason it may have to withdraw a block: the registry, a court, an upstream, or the end of its own right to the space. What matters is that the list is closed, that you get real notice, and what you are offered instead. Open wording such as "at our discretion" means the block is yours only until someone else wants it.

4. Term and notice

The initial term, how renewals run (monthly, quarterly, yearly) and how much notice either side gives. Check that the notice period leaves you time to renumber if you ever have to.

5. Price changes

Can the price rise during the term, how often, with how much notice, and can you leave if it rises a lot? A fixed price for the term, or a yearly change with an exit right, is the shape to look for.

6. What is included

The LOA, the ROA, route objects, reverse DNS, monitoring and abuse handling should be in the price, not an upsell at the moment you need them. Ask too whether there are setup fees and when they are waived.

7. Listings and abuse

What happens if an address is listed or abuse reports arrive: how long you have to fix it, whether the lessor helps, and whether there is a charge per listed address after a deadline. Short cure periods with high per-address penalties turn one compromised server into a large bill.

8. What you may use it for, and for whom

The acceptable use policy decides which services you may run on the addresses. Read it against your actual use. If you host or resell, check that you may sublease the space to your own customers without asking first.

9. Liability

Most contracts cap the lessor's liability; check the cap and what it excludes. A cap of a few months' fees is common. You cannot negotiate the internet's behavior into a contract, so the cap matters less than the clauses above that keep the block stable.

10. Which document wins, and which law applies

Where a signed agreement and published terms disagree, which one counts? And under which law, in which court? For a European business, a contract under the law of an EU member state and a court you can reach is worth more than it looks until the day you need it.

Where RTM Networks fits

Our Terms are public, and a signed agreement outranks them where the two differ. They say, among other things: we do not reclaim, reissue or renumber a block we lease to you, during the term or on renewal, and it costs nothing extra (the Block Continuity Guarantee); if we ever must withdraw a block, we give at least 60 days' written notice and offer an equivalent one; prices change at most once a year, with a month's notice and a right to leave if the rise exceeds 10%; you get 5 working days to fix a problem after a reasoned notice; you may sublease to your own clients without our consent; and Dutch law applies (terms of service, lease IPv4).