What is CGNAT and Does It Matter?
CGNAT (Carrier-Grade Network Address Translation) means you share a single public IP address with multiple households. Providers use it to save money because the global supply of unique IPv4 addresses has run out.
For most people, it runs invisibly in the background. But for power users and gamers, it introduces a few roadblocks — so it's worth understanding exactly what it does and doesn't affect before you pick a provider.
Why Do Providers Use CGNAT?
A public IPv4 address is a scarce resource. Rather than buying enough unique addresses for every customer, an ISP places many customers behind a single address and translates traffic in and out automatically. The customer's router still gets a private address (usually in the 100.64.0.0/10 range — a block reserved for carrier-grade NAT), and the ISP's equipment does the sharing.
This keeps wholesale costs down, and those savings usually show up in lower plan prices. The trade-off is that you no longer have a unique, reachable address on the public internet.
What Breaks Under CGNAT
- Console Gaming: It forces a "Strict NAT" (NAT Type 3) error on PlayStation, Xbox, and Switch. This makes it highly difficult to join multiplayer lobbies or use voice chat.
- Port Forwarding: You cannot direct incoming internet traffic to a specific device. This breaks home-hosted game servers, self-hosted websites, and media servers (like Plex).
- Direct Remote Access: Reaching home security cameras or storage drives from outside your network becomes incredibly complicated without using a third-party cloud service.
- Some VoIP and P2P applications that expect an inbound connection may misbehave, though most modern services work around it.
What Works Fine
- Web browsing, social media, and 4K streaming (Netflix, YouTube).
- Working from home (Zoom, Teams) and standard outbound VPN connections.
- Software updates, online banking, and essentially anything that initiates the connection from your side.
If all of your internet use fits in that second list, CGNAT will never be visible to you — a CGNAT provider's cheaper price is simply a better deal for you.
Is CGNAT Permanent?
No. A CGNAT address is assigned by your ISP's NAT equipment, not by you, and it can change without notice — often at every reconnect or session refresh. So even if your provider hands you a dynamic public IP, you still don't have a fixed address. If you need a stable address for a website, remote access, or a game server, you need a static IP, which most Australian providers sell as a paid add-on (typically $5–$10/month).
How to Bypass It
Every provider on NBN Tracker lists their CGNAT status, whether a CGNAT opt-out exists, and the cost of a static IP. You have three options:
- Free Opt-Out: Request a public IP from the provider after signing up. Some providers do this on request at no extra cost.
- Paid Static IP: Pay an extra $5–$10/month for a fixed public address.
- CGNAT-Free Providers: Choose an RSP that provides real public IPs by default.
You can filter and compare these policies side by side on our providers page before you commit.
FAQ
Does CGNAT slow down my internet?
No. CGNAT adds a negligible amount of translation overhead that you will not feel in day-to-day use. Your speeds are determined by your NBN tier and connection type, not by whether your ISP uses CGNAT.
Will a VPN fix the CGNAT gaming problem?
For outbound traffic, a VPN hides the CGNAT from the destination — many gamers use this to improve their NAT type. But a VPN cannot give you inbound port forwarding, so self-hosted game servers and direct remote access still won't work. For those use cases you need a public IP.
How can I tell if I'm on CGNAT right now?
Check your WAN IP address (shown by your router or at a site like whatismyip.com). If it falls in the 100.64.0.0 to 100.127.255.255 range, you are behind carrier-grade NAT.
Does IPv6 mean CGNAT no longer matters?
Increasingly, yes. With IPv6 and prefix delegation every device on your network gets its own globally unique address, which sidesteps the IPv4 sharing problem for services that support IPv6. But many consoles, games, and smaller services still depend on IPv4, so CGNAT remains relevant for now. Check the providers page for IPv6 and prefix delegation support.
Should I pay for a static IP if I self-host?
If you run a website, media server, or anything that needs inbound connections, a static IP (or a public IP plus a dynamic DNS service) is the only reliable option on the NBN. Port forwarding simply cannot work through CGNAT.