IPv6 included
Quietly future-proof
Every Cambridge Fibre line ships with full IPv6 — and a /48 of public address space — alongside IPv4. You don't have to do anything to use it. Your devices already speak it; the network just lets them. For most households this page will never matter. We've written it for the people who notice these things, and for everyone who simply wants to know that the line they're paying for is built for the next twenty years, not the last twenty.
Why we put it on every line
Direct device addressing
IPv6 gives every device on your network its own globally unique public address. That's how peer-to-peer applications, video calls, self-hosted services, and modern IoT products are designed to find each other. The address scheme doesn't get in their way.
A subnet you'll never outgrow
Every customer gets a /48 — that's 65,536 separate /64 networks of their own, each holding more addresses than the entire IPv4 internet. Hand subnets out to guest networks, IoT, the office in the spare room, the lab in the loft. You'll never run out and you'll never need to renumber.
Secure and private by default
The router we supply ships with the IPv6 firewall on out of the box — inbound connections happen only when you choose to allow them. And every modern phone, laptop, and tablet uses IPv6's built-in privacy addressing automatically, with no setup required.
Recognition
Recognised by the UK IPv6 Council
In 2022 we received the Jim Bound Award — the industry's recognition for ISPs whose real-world IPv6 traffic crosses the 20% threshold, measured independently at APNIC Labs. We've held that line every year since.
About the awardAddress space
What "/48" actually means
A short walk through the address structure, for the people who like to look under the bonnet.
The address itself
A 128-bit number, written as eight groups of four hex characters. The first 48 bits — your /48 — identify your network. We assign that to you. The remaining 80 bits split into a 16-bit subnet selector and a 64-bit interface ID, which are yours to use however suits you.
What you can build
Most homes use a single /64 from inside the /48 and never need to think about the rest. The router we supply takes care of all of this automatically — separate networks for guest Wi-Fi, IoT and smart-home devices, ready out of the box. Tinkerers and small businesses can step in and arrange their own /64s when they want to: lab kit, a home VPN, whatever fits.
It's static
Your /48 stays with your line, unchanged. Plan around it, build infrastructure on top of it, rely on it being there next year.
For everyone else
Will I notice?
No. That's the point. Your phones, laptops, smart TVs and games consoles all speak IPv6 already; turning the line on is enough. Most of the time you won't see anything different — IPv6 just sits in the background alongside IPv4, picked automatically by whichever happens to give the faster route to a given service.
What you do get is the certainty that you're on a network whose addressing scheme isn't running out. The IPv4 internet has been borrowing time since 2011. Yours isn't.
Built into every line, no extra charge
IPv6 with a /48 is part of every Cambridge Fibre residential broadband, business broadband, and Dedicated Internet Access product. Nothing to opt into. Nothing extra on the bill.