By Dr Alex J Martin-Smith, Strategic Lead
Direct answer: What is CGNAT and how it affects gaming and cameras in the UK? CGNAT is a broadband network setup where several customers share one public IPv4 address. It usually causes no issue for ordinary browsing, but it can prevent port forwarding, direct camera access and some peer to peer gaming connections.
- CGNAT is most likely to matter where you need incoming internet connections to reach your home network.
- Online gaming normally still works, but matchmaking, voice features or hosting can be less reliable in some games.
- Cameras using a manufacturer hosted remote viewing service may work normally, whilst direct access to a camera can fail.
- Before changing broadband, confirm whether CGNAT is the cause and ask whether a public IPv4 address is available.
What is CGNAT in UK broadband?
CGNAT means Carrier Grade Network Address Translation. It allows a broadband network to place many households behind a shared public IPv4 address, rather than allocating a separate public IPv4 address to every connection.
Your router still gives devices inside the home their own local addresses. The difference is at the point where your broadband connection reaches the wider internet. With a conventional public IPv4 address, an authorised incoming connection can be directed to your router if you configure port forwarding. Under CGNAT, the provider controls the shared address and cannot know which household should receive an unsolicited incoming request.
That design helps manage the limited supply of IPv4 addresses, but it changes what your connection can accept from outside. It is not automatically a sign of slow broadband, poor Wi‑Fi or a faulty router. It is an address allocation issue, so changing from FTTC to full fibre will not necessarily remove it.
Why does CGNAT affect gaming and cameras?
CGNAT affects services that expect the internet to start a connection into your home. Gaming and cameras are common examples because both may use direct connections rather than relying entirely on a hosted service.
| Activity | Likely effect of CGNAT | What to check |
|---|---|---|
| Playing online games | Often works, but some peer to peer sessions may be restricted. | Matchmaking, party joining and connection status. |
| Hosting a game | May fail because other players cannot reach your home network directly. | Whether the game needs an open inbound port. |
| Viewing cameras through an app | May work if the camera uses a hosted relay service. | Whether remote viewing depends on direct access. |
| Direct camera login | Port forwarding will usually not work under CGNAT. | Whether a public IP address is required. |
The practical point is that download speed is not the deciding factor here. A fast connection can still be behind CGNAT, and a modest connection with a public address may support direct remote access. Check the connection type as well as the speed and monthly cost.
How can I tell if my broadband uses CGNAT?
The clearest test is to compare the WAN or internet address shown in your router settings with the public IPv4 address shown by an independent internet address check. If they are different, CGNAT is a possible explanation.
An address beginning 100.64 to 100.127 is specifically reserved for shared address space and is a strong indication of CGNAT. Router WAN addresses beginning 10, 172.16 to 172.31, or 192.168 may also indicate an address that is not publicly reachable. However, router settings differ, and a local configuration issue can create similar results.
A support team can give the definitive answer. Ask a direct question: “Is this connection behind CGNAT, and can I have a public IPv4 address?” Also ask whether there is an extra charge, whether the address changes, and whether the option is available on the product you are considering. Record the answer before placing an order, particularly if cameras or gaming are essential.
Can I still play online games with CGNAT?
Yes, many people can play online games through CGNAT without noticing a problem. Most games begin with an outgoing connection from your console or computer, which CGNAT can handle. The difficulty appears where a game requires another player or service to initiate a connection back to your home.
Symptoms can include trouble joining certain friends, longer matchmaking, a restricted connection status, or an inability to host a private session. Results vary by game, platform, router and how the game handles peer to peer traffic. Do not assume that changing Wi‑Fi equipment will resolve a CGNAT restriction, although a wired connection can still improve stability inside the home.
If gaming is a priority, choose broadband on overall value first, then confirm the public IP policy before you switch. Full fibre, cable, FTTC, 4G and 5G describe access technologies, not a guaranteed public IPv4 arrangement.
Will security cameras work with CGNAT?
Cameras can work behind CGNAT, but the remote access method matters. A camera that connects out to a hosted viewing service can often send video to its app without needing a public IPv4 address. You may therefore be able to view alerts and live footage as usual.
Direct access is different. If you normally enter your home IP address, use a domain name that points to it, or forward a port in the router to reach a camera recorder, CGNAT will usually block that route. Port forwarding rules on your own router cannot override a shared address controlled beyond it.
Avoid exposing a camera or recorder directly to the internet merely to work around the problem. Check the device maker's supported secure remote access options, keep firmware current, use unique passwords and enable multi factor protection where available. If a direct connection is genuinely needed, a public IPv4 address is normally the straightforward requirement.
Is a public IP address the only solution to CGNAT?
A public IPv4 address is the most direct solution where you need conventional port forwarding. It allows your router to receive authorised incoming IPv4 traffic, subject to correct configuration and security controls. It may be dynamic, meaning it can change, or fixed, depending on the service.
IPv6 can also support direct addressing where the broadband service, router, camera or gaming setup, and the remote device all support it properly. It is not a universal replacement for public IPv4 because compatibility differs. A domain name service cannot by itself solve CGNAT either: it can track an address, but it cannot make a shared address accept traffic for one household.
For some camera systems, using the supported hosted remote viewing method is sufficient. For gaming, it may be enough to accept that a small number of peer to peer features could be limited. The right answer depends on what you actually need to connect to your home.
Should I change broadband because of CGNAT?
Change broadband because the overall service suits your address, budget and connection needs, not solely because CGNAT exists. Compare total contract cost, setup fees, contract length, expected installation timing and the provider's answer on public IPv4 availability. Prices, speeds and installation options are postcode specific and can change.
If you are moving home, confirm whether the same network type is available at the new address. FTTP availability can differ street by street, whilst 4G or 5G home broadband may have a different approach to public addressing. For a home office or micro business, treat remote access requirements as part of the service specification, alongside reliability and support.
If you decide to switch, One Touch Switch means you normally contact only the new provider for an eligible switch, rather than arranging the transfer with both providers (TOTSCo, 2024). Ask about any early termination charge before committing. From 17 January 2025, new contracts must show any mid contract price rises in pounds and pence at the point of sale, rather than using inflation linked formulas (Ofcom, 2024).
Can CGNAT cause problems with gaming cameras and port forwarding?
CGNAT can prevent incoming connections needed for port forwarding, direct camera access and some peer to peer gaming features. Ordinary web use and many online games can still work because they start connections from inside your home.
Does CGNAT make my broadband slower?
CGNAT is not a measure of broadband speed. It changes how public IPv4 connections are shared and routed. If your concern is slow downloads, poor Wi‑Fi coverage or dropouts, test those separately rather than assuming CGNAT is responsible.
Can I port forward with CGNAT?
Usually no. You can create a forwarding rule on your own router, but the shared public IPv4 address remains outside your control. Ask whether a public IPv4 address is available if port forwarding is essential for your setup.
Do cameras need a public IP address?
Not always. Cameras that use a supported hosted remote viewing service may work behind CGNAT. A public IPv4 address is normally needed only where you require direct inbound access to a camera or recorder through your own router.
Is CGNAT common on full fibre broadband?
CGNAT can be used on full fibre, FTTC, cable, 4G or 5G services. The access technology does not decide the public IP policy. Check the specific service before ordering if gaming hosting, cameras or remote access are important.
A public IP requirement should be checked before you sign, not discovered after installation. For a clear view of broadband options available at your exact address, enter your postcode on BroadbandSwitch.uk's comparison page and compare the full contract details alongside the connection type.