NatTypeTester
| Package | NuGet |
|---|
| Stun.Net |  |
Architecture
flowchart TD
Console["Console"] --> Application["Application"]
Desktop["Desktop"] --> Views["Views"]
Android["Android"] --> Views
Views --> Application
Views --> Configuration["Configuration"]
Views --> ViewModels["ViewModels"]
Application --> ApplicationContracts["Application.Contracts"]
Application --> Domain["Domain"]
Configuration --> Domain
ViewModels --> ApplicationContracts
ViewModels --> Domain
ApplicationContracts --> DomainShared["Domain.Shared"]
Domain --> DomainShared
RFC
- RFC 3489
- RFC 5780
- RFC 8489
Internet Protocol
Transmission Protocol
RFC3489
The STUN server has two IP addresses (IP1, IP2), each listening on two ports (Port1, Port2).
Send to X, request from Y means the request is sent to endpoint X, asking the server to reply from endpoint Y.
flowchart TD
T1["Test 1:<br>Send to IP1:Port1<br>request from IP1:Port1"] --> R1{"Received?"}
R1 -->|No| B1["UDP Blocked"]:::bad
R1 -->|Yes| R2{"Received<br>MappedEndpoint1 and<br>IP2:Port2?"}
R2 -->|No| B2["Unsupported Server"]:::bad
R2 -->|Yes| T2["Test 2:<br>Send to IP1:Port1<br>request from IP2:Port2"]
T2 --> D1{"MappedEndpoint1 is<br>link's IP endpoint?"}
D1 -->|Yes| R3{"Received?"}
R3 -->|No| W1["Symmetric UDP Firewall"]:::warn
R3 -->|Yes| R4{"Received from<br>IP2:Port2?"}
R4 -->|No| B3["Unsupported Server"]:::bad
R4 -->|Yes| G1["Open Internet"]:::good
D1 -->|"No (NAT)"| R5{"Received?"}
R5 -->|Yes| R6{"Received from<br>IP2:Port2?"}
R6 -->|No| B3
R6 -->|Yes| G2["Full Cone"]:::good
R5 -->|No| T12["Test 1(#35;2):<br>Send to IP2:Port2<br>request from IP2:Port2"]
T12 --> R7{"Received<br>MappedEndpoint1.2?"}
R7 -->|No| B4["Unknown"]:::bad
R7 -->|Yes| D2{"MappedEndpoint1.2<br>is MappedEndpoint1?"}
D2 -->|No| W2["Symmetric"]:::warn
D2 -->|Yes| T3["Test 3:<br>Send to IP1:Port1<br>request from IP1:Port2"]
T3 --> R8{"Received<br>MappedEndpoint3<br>from IP1:Port2?"}
R8 -->|No| M1["Port Restricted Cone"]:::mild
R8 -->|Yes| M2["Restricted Cone"]:::mild
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classDef warn fill:#ffe6cc,stroke:#d79b00,color:#000
classDef good fill:#7fe57f,stroke:#38761d,color:#000
classDef mild fill:#d9ead3,stroke:#93c47d,color:#000
RFC5389
The STUN server has two IP addresses (IP1, IP2), each listening on two ports (Port1, Port2).
Send to X, request from Y means the request is sent to endpoint X, asking the server to reply from endpoint Y.
Binding Test
Checking for UDP Connectivity with the STUN Server
flowchart TD
T1["Send to IP1:Port1<br>request from IP1:Port1"] --> R1{"Received?"}
R1 -->|No| B1["Fail"]:::bad
R1 -->|Yes| R2{"Received<br>MappedEndpoint?"}
R2 -->|No| B2["Unsupported Server"]:::bad
R2 -->|Yes| G1["Success"]:::good
classDef bad fill:#f4756b,stroke:#c0392b,color:#000
classDef good fill:#7fe57f,stroke:#38761d,color:#000
Mapping Behavior
Determining NAT Mapping Behavior
flowchart TD
T1["Test 1:<br>Send to IP1:Port1<br>request from IP1:Port1"] --> R1{"Received<br>MappedEndpoint1?"}
R1 -->|No| B1["Failed"]:::bad
R1 -->|Yes| R2{"Received<br>IP2:Port2?"}
R2 -->|No| B2["Unsupported Server"]:::bad
R2 -->|Yes| D1{"MappedEndpoint1 is<br>link's IP endpoint?"}
D1 -->|Yes| G1["Direct"]:::good
D1 -->|No| T2["Test 2:<br>Send to IP2:Port1<br>request from IP2:Port1"]
T2 --> R3{"Received<br>MappedEndpoint2?"}
R3 -->|No| B1
R3 -->|Yes| D2{"MappedEndpoint2<br>is MappedEndpoint1?"}
D2 -->|Yes| G2["Endpoint-Independent"]:::good
D2 -->|No| T3["Test 3:<br>Send to IP2:Port2<br>request from IP2:Port2"]
T3 --> R4{"Received<br>MappedEndpoint3?"}
R4 -->|No| B1
R4 -->|Yes| D3{"MappedEndpoint3<br>is MappedEndpoint2?"}
D3 -->|No| M1["Address and Port-Dependent"]:::mild
D3 -->|Yes| M2["Address-Dependent"]:::mild
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classDef good fill:#7fe57f,stroke:#38761d,color:#000
classDef mild fill:#d9ead3,stroke:#93c47d,color:#000
Filtering Behavior
Determining NAT Filtering Behavior
flowchart TD
T1["Test 1:<br>Send to IP1:Port1<br>request from IP1:Port1"] --> R1{"Received<br>MappedEndpoint1?"}
R1 -->|No| B1["Failed"]:::bad
R1 -->|Yes| R2{"Received<br>IP2:Port2?"}
R2 -->|No| B2["Unsupported Server"]:::bad
R2 -->|Yes| T2["Test 2:<br>Send to IP1:Port1<br>request from IP2:Port2"]
T2 --> R3{"Received?"}
R3 -->|Yes| R4{"Received from<br>IP2:Port2?"}
R4 -->|No| B3["Unsupported Server"]:::bad
R4 -->|Yes| G1["Endpoint-Independent"]:::good
R3 -->|No| T3["Test 3:<br>Send to IP1:Port1<br>request from IP1:Port2"]
T3 --> R5{"Received?"}
R5 -->|No| M1["Address and Port-Dependent"]:::mild
R5 -->|Yes| R6{"Received from<br>IP1:Port2?"}
R6 -->|No| B4["Unsupported Server"]:::bad
R6 -->|Yes| M2["Address-Dependent"]:::mild
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classDef good fill:#7fe57f,stroke:#38761d,color:#000
classDef mild fill:#d9ead3,stroke:#93c47d,color:#000
Combining Tests
flowchart TD
S1["Send to IP1:Port1<br>request from IP1:Port1"] --> R1{"Received?"}
R1 -->|No| B1["Binding Test:<br>Failed"]:::bad
R1 -->|Yes| R2{"Received<br>MappedEndpoint1?"}
R2 -->|No| B2["Binding Test:<br>Unsupported Server"]:::bad
R2 -->|Yes| OK1["Binding Test:<br>Success"]:::good
OK1 --> R3{"Received<br>IP2:Port2?"}
R3 -->|No| B3["Filtering Behavior:<br>Unsupported Server"]:::bad
R3 -->|Yes| S2["Send to IP1:Port1<br>request from IP2:Port2"]
S2 --> R4{"Received?"}
R4 -->|Yes| R5{"Received from<br>IP2:Port2?"}
R5 -->|No| B4["Filtering Behavior:<br>Unsupported Server"]:::bad
R5 -->|Yes| F1["Filtering Behavior:<br>Endpoint-Independent"]:::filt
R4 -->|No| S3["Send to IP1:Port1<br>request from IP1:Port2"]
S3 --> R6{"Received?"}
R6 -->|No| F3["Filtering Behavior:<br>Address and Port-Dependent"]:::filt
R6 -->|Yes| R7{"Received from<br>IP1:Port2?"}
R7 -->|No| B5["Filtering Behavior:<br>Unsupported Server"]:::bad
R7 -->|Yes| F2["Filtering Behavior:<br>Address-Dependent"]:::filt
F1 --> D1{"MappedEndpoint1 is<br>link's IP endpoint?"}
F2 --> D1
F3 --> D1
D1 -->|Yes| P1["Mapping Behavior:<br>Direct"]:::map
D1 -->|No| S4["Send to IP2:Port1<br>request from IP2:Port1"]
S4 --> R8{"Received<br>MappedEndpoint2?"}
R8 -->|No| B6["Mapping Behavior:<br>Failed"]:::bad
R8 -->|Yes| D2{"MappedEndpoint2<br>is MappedEndpoint1?"}
D2 -->|Yes| P2["Mapping Behavior:<br>Endpoint-Independent"]:::map
D2 -->|No| S5["Send to IP2:Port2<br>request from IP2:Port2"]
S5 --> R9{"Received<br>MappedEndpoint3?"}
R9 -->|No| B6
R9 -->|Yes| D3{"MappedEndpoint3<br>is MappedEndpoint2?"}
D3 -->|No| P3["Mapping Behavior:<br>Address and Port-Dependent"]:::map
D3 -->|Yes| P4["Mapping Behavior:<br>Address-Dependent"]:::map
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classDef good fill:#7fe57f,stroke:#38761d,color:#000
classDef filt fill:#d9d2e9,stroke:#8e7cc3,color:#000
classDef map fill:#f8cde0,stroke:#c27ba0,color:#000
