NAT Type Test: Open, Moderate or Strict
Your NAT type decides whether other players can reach you directly. It is the most common cause of multiplayer problems that have nothing to do with your speed: endless matchmaking, parties that will not connect, voice chat that works for everyone except you. The test on the front page reports it while it measures, and this page explains what the answer means.
What this test can actually see
Be clear about what is being measured, because most pages on this subject are not. A console prints NAT Type 1, 2 or 3 after probing its own connection. A browser cannot read that value, and any site claiming to show you your console's NAT type is guessing.
What a browser can do is build a real peer connection and then ask which kind of network path succeeded. That is the same mechanism — ICE, the standard that WebRTC uses to get through NATs — that a game uses when it tries to connect you to another player. The result comes in three kinds, and they map onto the console labels closely enough to be useful:
Open — direct path
The connection used a host candidate: your machine is reachable at a public address, with nothing rewriting your traffic in between.
Roughly the console's Type 1. Nothing to fix. If you still cannot connect to a game, the cause is elsewhere.
Moderate — behind NAT, traversable
The connection used a server-reflexive candidate: you are behind a router doing NAT, but it allowed a direct path once both sides had been introduced to each other.
Roughly the console's Type 2, and by far the most common result. Normal, and fine for almost every game.
Strict — relay required
No direct path could be built at all. The connection only worked through a relay server in the middle, forwarding every packet.
Roughly the console's Type 3. This is the one that causes matchmaking and party problems, and it is usually not your router's fault — see below.
Why "Strict" is usually your provider, not your router
The single most common reason for a strict result in 2026 is CGNAT — Carrier-Grade NAT. IPv4 addresses ran out, so many providers no longer give each customer one. Instead, hundreds or thousands of customers share a public address, and the provider's own equipment rewrites the traffic. Your router is then not the outermost NAT on your path, and no setting inside it can change that.
Mobile broadband is nearly always CGNAT. Fixed-line providers vary by country and by tariff — it is common on cable and fibre plans sold as "consumer" packages, less common where a static IPv4 address is included.
Two signs, both of which you can check in a minute:
- Compare two addresses. Look up the WAN or internet address in your router's status page, then look at the IP shown at the top of the front page. If your router says
100.64.x.xto100.127.x.x(or10.x,172.16–31.x,192.168.x) while the site shows something else entirely, there is a second NAT above you and it belongs to your provider. - Port forwarding does nothing. If you forward a port, the rule is active in the router, and the port is still unreachable from outside, you are behind CGNAT. The rule is correct; it just is not the last hop any more.
What actually fixes a strict NAT
- Ask your provider for a public IPv4 address. The one measure that resolves CGNAT. Many providers hand one out free on request, some charge a small monthly fee, some only offer it on business tariffs. Ask for a "public IPv4" or "no CGNAT" — asking for a static IP is a different, usually more expensive product than the one you need.
- Enable UPnP or NAT-PMP in your router if you are not behind CGNAT. It lets games open their own ports. It is also the setting most often turned off by a well-meaning guide; if a game's own network test complains, this is the first thing to check.
- Forward the ports the game documents, if you would rather not run UPnP. More work, more precise, and it must be redone per game.
- Turn on IPv6 if your provider offers it. IPv6 has no NAT, and a growing number of games will use it in preference. It often resolves party and matchmaking problems even while the IPv4 side stays strict.
- Take one router out of the path. Two routers chained together (a provider box plus your own) create two layers of NAT. Putting the provider's box into bridge or modem mode leaves exactly one.
What NAT type does not explain
This is where most guides overpromise, so: a strict NAT does not cause packet loss, it does not raise your ping to a game server, and it does not make your connection unstable. It affects who can reach you and how — connecting to other players, joining parties, hosting, peer-to-peer matches. A relayed path can add some latency because packets take a detour, but if your line is dropping packets or your ping swings by 80 ms, the NAT type is not the reason and changing it will not help.
Those problems have their own measurement, which is the rest of this site: run the packet loss test and read how it measures before you change any router setting.
How to read the result on the front page
The line appears in the status row above the chart, as soon as the connection has been established — usually within a second or two of the page opening. It is the type of the path that actually carried the measurement, not a prediction.
One case deserves its own note: if your network blocks UDP entirely, the test falls back to a TCP connection so that it can still measure something, and the line says so instead of reporting a NAT type. That fallback is disclosed on the methodology page too, because it changes what the packet loss figure means.
Frequently Asked Questions
Can a website really tell me my NAT type?
It can tell you something equivalent, and it should say which. A console prints "NAT Type 1/2/3" after probing its own connection, and no browser can read that value. What this site does instead is build a real peer connection and report which kind of path succeeded - host, server-reflexive or relay. That is the same mechanism a game uses to connect you to another player, so it answers the question you actually have. Anything claiming to show your console's number is guessing.
What is CGNAT and how do I know if I am behind it?
Carrier-Grade NAT means your provider shares one public IPv4 address between many customers and rewrites the traffic on their own equipment. Two signs: the WAN address in your router is in the 100.64-100.127 range (or a private range) while this site shows a different public IP, and port forwarding has no effect no matter how correctly you set it up. Mobile broadband is almost always CGNAT.
Does a strict NAT cause packet loss or high ping?
No. NAT affects who can reach you and how - connecting to other players, joining parties, hosting matches. It does not drop packets and it does not add latency to a game server, though a relayed path can add some because the traffic takes a detour. If your line is losing packets or your ping swings, that is a different problem with a different measurement, and changing your NAT type will not fix it.
How do I get an open NAT?
If you are not behind CGNAT: enable UPnP or NAT-PMP in your router, or forward the ports your game documents, and make sure you do not have two routers chained together. If you are behind CGNAT, none of that can work - ask your provider for a public IPv4 address. Many hand one out free on request. Enabling IPv6, where your provider offers it, often resolves party and matchmaking problems on its own because IPv6 has no NAT at all.
Why does the test say "UDP blocked" instead of a NAT type?
Because something on your network - a corporate firewall, a restrictive VPN, occasionally hotel or campus Wi-Fi - is blocking UDP entirely. The measurement then falls back to a TCP connection so it can still show you something, but no NAT type was established, and the packet loss figure means something different because TCP hides loss by retransmitting. That is why the line says so rather than reporting a type.