### Example Bug Report

Source: https://github.com/apple/swift-nio-ssl/blob/main/CONTRIBUTING.md

An example of a comprehensive bug report, including SwiftNIO commit hash, context, reproduction steps, Swift version, OS version, and system information.

```text
SwiftNIO commit hash: 22ec043dc9d24bb011b47ece4f9ee97ee5be2757

Context:
While load testing my HTTP web server written with SwiftNIO, I noticed
that one file descriptor is leaked per request.

Steps to reproduce:
1. ...
2. ...
3. ...
4. ...

$ swift --version
Swift version 4.0.2 (swift-4.0.2-RELEASE)
Target: x86_64-unknown-linux-gnu

Operating system: Ubuntu Linux 16.04 64-bit

$ uname -a
Linux beefy.machine 4.4.0-101-generic #124-Ubuntu SMP Fri Nov 10 18:29:59 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

My system has IPv6 disabled.
```

--------------------------------

### Run NIOTLSServer

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOTLSServer/README.md

Invoke the NIOTLSServer application to start a TLS server on ::1, port 4433.

```bash
swift run NIOTLSServer # Gets a content on a server on ::1, port 4433, using TLS

```

--------------------------------

### Configure SwiftNIO SSL Client

Source: https://github.com/apple/swift-nio-ssl/blob/main/README.md

Set up TLS configuration for a client. The handler must be initialized within the `channelInitializer`.

```swift
let configuration = TLSConfiguration.makeClientConfiguration()
let sslContext = try NIOSSLContext(configuration: configuration)

let client = ClientBootstrap(group: group)
    .channelInitializer { channel in
        // important: The handler must be initialized _inside_ the `channelInitializer`
        let handler = try NIOSSLClientHandler(context: sslContext)

        [...] 
        channel.pipeline.syncOperations.addHandler(handler)
        [...] 
    }
```

--------------------------------

### Configure SwiftNIO SSL Server

Source: https://github.com/apple/swift-nio-ssl/blob/main/README.md

Set up TLS configuration for a server using a certificate chain and private key. The handler must be initialized within the `childChannelInitializer`.

```swift
let configuration = TLSConfiguration.makeServerConfiguration(
    certificateChain: try NIOSSLCertificate.fromPEMFile("cert.pem").map { .certificate($0) },
    privateKey: try .privateKey(.init(file: "key.pem", format: .pem))
)
let sslContext = try NIOSSLContext(configuration: configuration)

let server = ServerBootstrap(group: group)
    .childChannelInitializer { channel in
        // important: The handler must be initialized _inside_ the `childChannelInitializer`
        let handler = NIOSSLServerHandler(context: sslContext)

        [...] 
        channel.pipeline.syncOperations.addHandler(handler)
        [...] 
    }
```

--------------------------------

### Invoke NIOSSLHTTP1Client with a Specific URL

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSLHTTP1Client/README.md

Use this command to fetch content from a specified server (e.g., example.com) on the default HTTPS port (443) using SSL/TLS. The URL dictates the target host and port.

```bash
swift run NIOSSLHTTP1Client "https://example.com"
```

--------------------------------

### Invoke NIOSSLHTTP1Client with Default Server

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSLHTTP1Client/README.md

Use this command to fetch content from a server on localhost (::1) on the default HTTPS port (443) using SSL/TLS. No URL is specified, so defaults are used.

```bash
swift run NIOSSLHTTP1Client
```

--------------------------------

### Inspecting Pre-Shared Key Configurations

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/TLSConfiguration.md

Details for inspecting pre-shared key (PSK) configurations for clients and servers.

```APIDOC
## Inspecting pre-shared key configurations

- ``pskClientProvider``
- ``pskHint``
- ``pskServerProvider``
- ``pskClientCallback``
- ``pskServerCallback``
```

--------------------------------

### Invoke NIOSSLHTTP1Client with Custom Port

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSLHTTP1Client/README.md

Use this command to fetch content from a specified server (e.g., example.com) on a custom HTTPS port (e.g., 4433) using SSL/TLS. This is useful when the server is not listening on the default port.

```bash
swift run NIOSSLHTTP1Client "https://example.com:4433"
```

--------------------------------

### Creating TLS Configurations

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/TLSConfiguration.md

Provides methods for creating default client configurations and custom server configurations.

```APIDOC
## Creating a TLS configuration

- ``clientDefault``
- ``makeClientConfiguration()``
- ``makeServerConfiguration(certificateChain:privateKey:)``
- ``makePreSharedKeyConfiguration()``
```

--------------------------------

### Server TLS Configuration

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/index.md

Configure a server to use TLS by providing a certificate chain and private key. The TLSConfiguration is then used to create a NIOSSLContext, which initializes the NIOSSLServerHandler. Ensure the handler is added within the childChannelInitializer.

```swift
let configuration = TLSConfiguration.makeServerConfiguration(
    certificateChain: try NIOSSLCertificate.fromPEMFile("cert.pem").map { .certificate($0) },
    privateKey: try .privateKey(.init(file: "key.pem", format: .pem))
)
let sslContext = try NIOSSLContext(configuration: configuration)

let server = ServerBootstrap(group: group)
    .childChannelInitializer { channel in
        // important: The handler must be initialized _inside_ the `childChannelInitializer`
        let handler = NIOSSLServerHandler(context: sslContext)

        [...] // Other channel setup
        channel.pipeline.addHandler(handler)
        [...] // More channel setup
    }
```

--------------------------------

### Deprecated Client TLS Configuration Initializers

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/TLSConfiguration.md

Deprecated methods for creating client TLS configurations with various options.

```APIDOC
## Deprecated initializers

- ``forClient(cipherSuites:minimumTLSVersion:maximumTLSVersion:certificateVerification:trustRoots:certificateChain:privateKey:applicationProtocols:shutdownTimeout:keyLogCallback:)``
- ``forClient(cipherSuites:minimumTLSVersion:maximumTLSVersion:certificateVerification:trustRoots:certificateChain:privateKey:applicationProtocols:shutdownTimeout:keyLogCallback:renegotiationSupport:)``
- ``forClient(cipherSuites:verifySignatureAlgorithms:signingSignatureAlgorithms:minimumTLSVersion:maximumTLSVersion:certificateVerification:trustRoots:certificateChain:privateKey:applicationProtocols:shutdownTimeout:keyLogCallback:renegotiationSupport:)``
```

--------------------------------

### Configure TLS for Post-Quantum Key Exchange Only

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/quantum-secure-tls.md

Set the TLS configuration to use only the post-quantum key exchange curve. This ensures that all key establishment is resistant to quantum computing attacks.

```swift
tlsConfiguration.curves = [.x25519_MLKEM768]
```

--------------------------------

### Client TLS Configuration

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/index.md

Configure a client for TLS connections. This basic client configuration does not require a certificate chain or private key. The TLSConfiguration is used to create a NIOSSLContext, which initializes the NIOSSLClientHandler. Ensure the handler is added within the channelInitializer.

```swift
let configuration = TLSConfiguration.makeClientConfiguration()
let sslContext = try NIOSSLContext(configuration: configuration)

let client = ClientBootstrap(group: group)
    .channelInitializer { channel in
        // important: The handler must be initialized _inside_ the `channelInitializer`
        let handler = try NIOSSLClientHandler(context: sslContext)

        [...] // Other channel setup
        channel.pipeline.addHandler(handler)
        [...] // More channel setup
    }
```

--------------------------------

### Deprecated Server TLS Configuration Initializers

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/TLSConfiguration.md

Deprecated methods for creating server TLS configurations with various options.

```APIDOC
- ``forServer(certificateChain:privateKey:cipherSuites:minimumTLSVersion:maximumTLSVersion:certificateVerification:trustRoots:applicationProtocols:shutdownTimeout:keyLogCallback:)``
- ``forServer(certificateChain:privateKey:cipherSuites:verifySignatureAlgorithms:signingSignatureAlgorithms:minimumTLSVersion:maximumTLSVersion:certificateVerification:trustRoots:applicationProtocols:shutdownTimeout:keyLogCallback:)``
```

--------------------------------

### Configure Git Commit Template

Source: https://github.com/apple/swift-nio-ssl/blob/main/CONTRIBUTING.md

Command to configure Git to use the SwiftNIO commit message template. This ensures commit messages adhere to the project's standards.

```bash
git config commit.template dev/git.commit.template
```

--------------------------------

### Comparing and Hashing TLS Configurations

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/TLSConfiguration.md

Methods for comparing and hashing TLS configurations.

```APIDOC
## Comparing and Hashing TLS configurations

- ``bestEffortEquals(_:)``
- ``bestEffortHash(into:)``
```

--------------------------------

### Inspecting Cipher Configurations

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/TLSConfiguration.md

Provides access to information about cipher suites, signature algorithms, and supported curves.

```APIDOC
## Inspecting configuration ciphers

- ``cipherSuites``
- ``verifySignatureAlgorithms``
- ``signingSignatureAlgorithms``
- ``cipherSuiteValues``
- ``curves``
- ``additionalTrustRoots``
- ``sendCANameList``
```

--------------------------------

### Inspecting TLS Configuration

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/TLSConfiguration.md

Allows inspection of various TLS settings such as minimum/maximum TLS versions, certificate verification, and application protocols.

```APIDOC
## Inspecting a configuration

- ``minimumTLSVersion``
- ``maximumTLSVersion``
- ``certificateVerification``
- ``trustRoots``
- ``certificateChain``
- ``privateKey``
- ``applicationProtocols``
- ``shutdownTimeout``
- ``keyLogCallback``
- ``renegotiationSupport``
- ``sslContextCallback``
```

--------------------------------

### Configure TLS for Classical Key Exchange Only

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/quantum-secure-tls.md

Set the TLS configuration to use only classical key exchange curves, disabling post-quantum cryptography. This is useful if post-quantum support is not required or causes compatibility issues.

```swift
tlsConfiguration.curves = [.x25519, .secp256r1, .secp384r1]
```

--------------------------------

### View System Certificate Validation Logs

Source: https://github.com/apple/swift-nio-ssl/blob/main/Sources/NIOSSL/Docs.docc/trust-roots-behavior.md

Use this command on macOS/iOS to view detailed certificate validation errors from the system's security subsystem. This can help diagnose issues related to certificate formatting, missing extensions, or chain validation problems.

```bash
log show --predicate 'subsystem == "com.apple.security"' --last 1m
```

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