Online NAT Type Checker
What is NAT?
NAT stands for Network Address Translation and is the conversion of a packet’s source or destination IP address in order to forward the data packets over the network. There are four core types of NAT:
- Full Cone NAT: Any external address and port may access an internal resource as long as the internal resource is contacted first
- Restricted Cone NAT: An external IP address can connect to an internal resource only if it has previously interacted with it
- Port Restricted Cone NAT: Only if an external IP address and port has interacted through that port with the internal resource it has the accessibility on the external address and port
- Symmetric NAT: When packets are sent to an external IP address and port, while being replied from the same, different handles will be provided to the external IP address and port. When two different outside users attempt to connect to the same internal address with the same port number, each will receive a different number
The techniques used in the identification of NAT include port availability and the state of the Internet connection to determine which of the four types of NAT is being used in the network
How does NAT type influence your connection?
NAT also refers to method whereby routers enable many local devices to share a single public IP address when connecting to the internet. This makes it easy to save IP addresses and to increase the security by effectively hiding internal networks’s addresses.
NAT does not pose much of a problem on normal web browsing, where one opens a webpage or watches a video; however, it is a challenge on P2P connections. Gaming, video, or micro-conferencing that mostly employ direct device to device connection may be affected by a kind of NAT type:
- Full Cone: Few constraints, it is easy to connect to another network
- Restricted Cone and Port Restricted Cone: Restricted access but can join the majority of the networks
- Symmetric NAT: Very limited, it results in interaction issues with the community particularly in playing games or attending virtual meetings
Namely, your network behind Symmetric NAT can only make connections to computers in other private networks if the latter allows incoming connections as well. However, media data needs to be sent through a public server like relay or TURN server which has the drawback of introducing more delay and lesser connection quality.
Selecting the right NAT is very important for creating fluent experiences when using the Internet, especially for activities that involve establishment of direct P2P connections.
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