Cuckoo customers moved to Onestream have lost their static IPs
Some of the households moved from Cuckoo to Onestream this year have found that the fixed IP address they used to have has gone, and they are getting mixed answers about whether it is coming back. ISPreview reports that customers bulk migrated after Cuckoo’s customer base was sold in May 2026, and who previously had a static IP, have been put on CGNAT connections instead, where one public address is shared between several homes rather than given to a single line.
The answers have not been consistent. On the feedback ISPreview says it has seen, affected customers were first told the provider knew about the problem and was working on it, and at least one support agent floated the idea that a fix might mean agreeing a new contract. Then a reader who put in a complaint was told this week that Onestream does “not currently offer IP addresses without CGNAT”. Nothing about a plan to add it. ISPreview also notes that Cuckoo still seems to be handling most of the support replies for the migrated customers, which is unusual this far into a takeover.
What does CGNAT actually stop you doing?
For most people, nothing they would notice. Browsing, streaming, video calls and ordinary online gaming all work fine on a shared address. What breaks is anything that needs the outside world to start the conversation: viewing a home security camera while you are out, reaching a network drive at home, port forwarding, hosting a game server, and some remote access setups that expect your line to have an address of its own. That is a minority of households. For them it is not a niggle, because no setting inside the house fixes it. We wrote about the other side of this when Giant turned IPv6 on for the same reason.
What can you do about it?
If this is you, the formal route is a complaint to the provider first, and then the independent scheme it belongs to if the answer will not do. Our guide to complaining about your broadband provider sets out the order and what to keep a record of. Whether losing a feature counts as a change you can leave over depends on what your contract actually promised you, and what happens when your provider is taken over covers where a migrated customer stands.
The honest gap here is scale. All of this rests on the feedback one outlet has seen and one reader’s complaint, and neither Cuckoo nor Onestream has published a policy either way, so there is no way of knowing how many of the migrated lines are affected. The wider lesson holds anyway. A static IP is rarely advertised, it is easily lost in a migration, and it is worth confirming in writing before you order rather than after. If you need one and your provider has none to offer, the answer is a different provider. Our availability checker shows which networks reach your street.