# NAT Score

#### **NAT Score**$$M\_{IP}$$

The NAT (Network Address Translation) type plays a crucial role in determining the quality and stability of connections. As such, we have established a differentiated rewards system based on the type of NAT to encourage optimal connectivity configurations. Below is the classification of NAT types along with their corresponding reward coefficients:

| NAT Classification           | Reward Coefficient |
| ---------------------------- | ------------------ |
| Public IP (Not NAT)          | 2                  |
| NAT 1 (Full Cone NAT)        | 1.5                |
| NAT 2 (Restricted Cone)      | 1.3                |
| NAT 3 (Port Restricted Cone) | 1.1                |
| NAT 4 (Symmetric)            | 0.8                |

#### **Supplementary Information on NAT Types**

**NAT 1**: Full Cone NAT This is the most permissive type of network environment. It imposes no restrictions on IP addresses or ports, allowing for unhindered network communications.

**NAT 2**: Address-Restricted Cone NAT Building on NAT1, NAT2 introduces address restrictions. While IP addresses are restricted under this type, ports remain unrestricted, offering a slightly more controlled environment than Full Cone NAT.

**NAT 3**: Port-Restricted Cone NAT NAT3 goes a step further by adding port restrictions in addition to IP restrictions. This means both IP addresses and ports are controlled, tightening network security and reducing some flexibility in connectivity.

**NAT 4**: Symmetric NAT Symmetric NAT incorporates the restrictive features of Port-Restricted Cone NAT. Every internal request to a specific external address may be assigned a new port number. Consequently, port numbers associated with different external addresses can vary, often hindering peer-to-peer (P2P) communications due to its strict nature.