# HTTPS/TLS Setup Guide - Svrnty.MCP.Server

**Purpose**: Production-grade HTTPS/TLS configuration for secure MCP server deployment
**Audience**: DevOps engineers, system administrators
**Last Updated**: 2025-10-19
**Version**: 1.0.0

---

## Table of Contents

1. [Overview](#overview)
2. [Prerequisites](#prerequisites)
3. [Development Setup](#development-setup)
4. [Production Setup](#production-setup)
5. [Certificate Management](#certificate-management)
6. [Security Headers (HSTS)](#security-headers-hsts)
7. [Testing HTTPS](#testing-https)
8. [Troubleshooting](#troubleshooting)

---

## Overview

Svrnty.MCP.Server supports HTTPS/TLS through ASP.NET Core's Kestrel web server. This guide covers configuration for both development and production environments.

**Security Benefits:**
- Encrypted communication (prevents eavesdropping)
- Client/server authentication
- Data integrity verification
- Compliance with security best practices

**Default Behavior:**
- HTTP only (for development ease)
- HTTPS must be explicitly configured
- Uses Kestrel's built-in TLS support

---

## Prerequisites

### Development
- .NET 8.0 SDK
- OpenSSL or dotnet dev-certs tool
- PowerShell (Windows) or bash (Linux/macOS)

### Production
- Valid TLS certificate (from CA or Let's Encrypt)
- Private key file
- Certificate chain (intermediate + root CA certs)
- Reverse proxy (optional): Nginx, Traefik, or Kestrel standalone

---

## Development Setup

### Option 1: ASP.NET Core Development Certificate (Recommended)

**Step 1: Generate Development Certificate**

**Windows / macOS / Linux:**
```bash
# Generate and trust dev certificate
dotnet dev-certs https --trust

# Verify installation
dotnet dev-certs https --check
```

**Step 2: Configure appsettings.Development.json**

Create or update `appsettings.Development.json` in the Server project:

```json
{
  "Kestrel": {
    "Endpoints": {
      "Http": {
        "Url": "http://localhost:5050"
      },
      "Https": {
        "Url": "https://localhost:5051",
        "Certificate": {
          "Subject": "CN=localhost",
          "Store": "My",
          "Location": "CurrentUser",
          "AllowInvalid": true
        }
      }
    }
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  }
}
```

**Step 3: Run Server with HTTPS**

```bash
cd Svrnty.MCP.Server/samples/CodexMcpServer
dotnet run --environment Development

# Server will listen on:
# - HTTP:  http://localhost:5050
# - HTTPS: https://localhost:5051
```

**Step 4: Test HTTPS Endpoint**

```bash
# Test health endpoint
curl -k https://localhost:5051/health

# Test MCP invoke endpoint
curl -k -X POST https://localhost:5051/mcp/invoke \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your-api-key" \
  -d '{
    "jsonrpc": "2.0",
    "method": "tools/list",
    "id": "1"
  }'
```

> **Note**: `-k` flag skips certificate validation (dev only!)

### Option 2: Custom Development Certificate with OpenSSL

**Step 1: Generate Self-Signed Certificate**

```bash
# Create directory for certs
mkdir -p /home/svrnty/codex/Svrnty.MCP.Server/certs

# Generate private key
openssl genrsa -out certs/localhost.key 2048

# Generate certificate signing request (CSR)
openssl req -new -key certs/localhost.key -out certs/localhost.csr \
  -subj "/C=CA/ST=Quebec/L=Montreal/O=Svrnty/CN=localhost"

# Generate self-signed certificate (valid for 365 days)
openssl x509 -req -days 365 -in certs/localhost.csr \
  -signkey certs/localhost.key -out certs/localhost.crt

# Convert to PFX format (required by Kestrel)
openssl pkcs12 -export -out certs/localhost.pfx \
  -inkey certs/localhost.key -in certs/localhost.crt \
  -passout pass:YourSecurePassword
```

**Step 2: Configure appsettings.Development.json**

```json
{
  "Kestrel": {
    "Endpoints": {
      "Https": {
        "Url": "https://localhost:5051",
        "Certificate": {
          "Path": "certs/localhost.pfx",
          "Password": "YourSecurePassword"
        }
      }
    }
  }
}
```

**Security**: Add `certs/` directory to `.gitignore` to avoid committing private keys.

---

## Production Setup

### Option 1: Certificate from File (Recommended for Kubernetes/Docker)

**Step 1: Obtain Production Certificate**

Use one of:
- **Let's Encrypt** (free, automated renewal)
- **Commercial CA** (DigiCert, Sectigo, etc.)
- **Internal PKI** (corporate certificate authority)

**Step 2: Prepare Certificate Files**

Ensure you have:
- `server.crt` - Server certificate
- `server.key` - Private key
- `ca-bundle.crt` - Intermediate + root CA certificates (optional)

**Step 3: Convert to PFX Format**

```bash
# Combine cert + key + chain into PFX
openssl pkcs12 -export -out server.pfx \
  -inkey server.key \
  -in server.crt \
  -certfile ca-bundle.crt \
  -passout pass:ProductionSecurePassword
```

**Step 4: Deploy Certificate**

**Docker/Kubernetes:**
```bash
# Create Kubernetes secret
kubectl create secret generic mcp-server-tls \
  --from-file=server.pfx=server.pfx \
  --from-literal=password=ProductionSecurePassword

# Mount in deployment
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mcp-server
spec:
  template:
    spec:
      containers:
      - name: mcp-server
        volumeMounts:
        - name: tls-cert
          mountPath: /app/certs
          readOnly: true
        env:
        - name: CERTIFICATE_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mcp-server-tls
              key: password
      volumes:
      - name: tls-cert
        secret:
          secretName: mcp-server-tls
```

**Step 5: Configure appsettings.Production.json**

```json
{
  "Kestrel": {
    "Endpoints": {
      "Https": {
        "Url": "https://*:5051",
        "Certificate": {
          "Path": "/app/certs/server.pfx",
          "Password": ""  // Read from environment variable
        },
        "Protocols": "Http1AndHttp2"
      }
    }
  },
  "AllowedHosts": "*"
}
```

**Step 6: Set Environment Variable for Password**

```bash
export KESTREL__CERTIFICATES__DEFAULT__PASSWORD="ProductionSecurePassword"
```

Or in `docker-compose.yml`:
```yaml
services:
  mcp-server:
    environment:
      - KESTREL__CERTIFICATES__DEFAULT__PASSWORD=${CERTIFICATE_PASSWORD}
    volumes:
      - ./certs/server.pfx:/app/certs/server.pfx:ro
```

### Option 2: Certificate from Azure Key Vault

**Step 1: Store Certificate in Key Vault**

```bash
az keyvault certificate import \
  --vault-name your-keyvault \
  --name mcp-server-cert \
  --file server.pfx \
  --password ProductionSecurePassword
```

**Step 2: Configure appsettings.Production.json**

```json
{
  "Kestrel": {
    "Endpoints": {
      "Https": {
        "Url": "https://*:5051",
        "Certificate": {
          "KeyVaultUri": "https://your-keyvault.vault.azure.net/",
          "CertificateName": "mcp-server-cert"
        }
      }
    }
  }
}
```

**Step 3: Grant Managed Identity Access**

```bash
az keyvault set-policy \
  --name your-keyvault \
  --object-id <managed-identity-object-id> \
  --certificate-permissions get
```

### Option 3: Reverse Proxy (Nginx/Traefik) with TLS Termination

**Best for**: Load balancing, multiple servers, centralized certificate management

**Architecture**:
```
Client → HTTPS → Nginx/Traefik (TLS termination) → HTTP → MCP Server (5050)
```

**Nginx Configuration** (`/etc/nginx/sites-available/mcp-server`):

```nginx
server {
    listen 443 ssl http2;
    server_name mcp.example.com;

    ssl_certificate /etc/nginx/ssl/server.crt;
    ssl_certificate_key /etc/nginx/ssl/server.key;

    # Modern TLS configuration
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers 'ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256';
    ssl_prefer_server_ciphers off;

    # HSTS
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;

    location / {
        proxy_pass http://localhost:5050;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

# Redirect HTTP to HTTPS
server {
    listen 80;
    server_name mcp.example.com;
    return 301 https://$server_name$request_uri;
}
```

**Traefik Configuration** (`docker-compose.yml`):

```yaml
services:
  traefik:
    image: traefik:v2.10
    command:
      - "--api.insecure=true"
      - "--providers.docker=true"
      - "--entrypoints.web.address=:80"
      - "--entrypoints.websecure.address=:443"
      - "--certificatesresolvers.letsencrypt.acme.tlschallenge=true"
      - "--certificatesresolvers.letsencrypt.acme.email=admin@example.com"
      - "--certificatesresolvers.letsencrypt.acme.storage=/letsencrypt/acme.json"
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock:ro"
      - "./letsencrypt:/letsencrypt"

  mcp-server:
    image: openharbor/mcp-server:latest
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.mcp.rule=Host(`mcp.example.com`)"
      - "traefik.http.routers.mcp.entrypoints=websecure"
      - "traefik.http.routers.mcp.tls.certresolver=letsencrypt"
      - "traefik.http.services.mcp.loadbalancer.server.port=5050"
```

---

## Certificate Management

### Automatic Renewal with Let's Encrypt

**Using Certbot:**

```bash
# Install certbot
sudo apt-get install certbot

# Obtain certificate
sudo certbot certonly --standalone -d mcp.example.com

# Certificates location: /etc/letsencrypt/live/mcp.example.com/
# - fullchain.pem (certificate + chain)
# - privkey.pem (private key)

# Convert to PFX for Kestrel
sudo openssl pkcs12 -export \
  -out /etc/letsencrypt/live/mcp.example.com/server.pfx \
  -inkey /etc/letsencrypt/live/mcp.example.com/privkey.pem \
  -in /etc/letsencrypt/live/mcp.example.com/fullchain.pem \
  -passout pass:YourSecurePassword

# Auto-renewal (certbot creates cron job automatically)
sudo certbot renew --dry-run
```

### Certificate Rotation

**Step 1: Update Certificate File**

Replace `server.pfx` with new certificate.

**Step 2: Reload Without Downtime**

```bash
# Docker
docker exec mcp-server kill -HUP 1

# Kubernetes
kubectl rollout restart deployment/mcp-server

# Systemd
sudo systemctl reload mcp-server
```

**Step 3: Verify New Certificate**

```bash
echo | openssl s_client -connect mcp.example.com:443 -servername mcp.example.com 2>/dev/null | openssl x509 -noout -dates
```

---

## Security Headers (HSTS)

**HTTP Strict Transport Security (HSTS)** forces browsers to use HTTPS.

**Method 1: Kestrel Middleware** (Recommended)

Update `Program.cs` in `CodexMcpServer`:

```csharp
var builder = WebApplication.CreateBuilder(args);

var app = builder.Build();

// Add HSTS middleware (production only)
if (!app.Environment.IsDevelopment())
{
    app.UseHsts();
}

// Redirect HTTP to HTTPS
app.UseHttpsRedirection();

// ... rest of configuration
app.Run();
```

**Method 2: Custom Middleware**

```csharp
app.Use(async (context, next) =>
{
    if (!context.Request.IsHttps)
    {
        var httpsUrl = $"https://{context.Request.Host}{context.Request.Path}{context.Request.QueryString}";
        context.Response.Redirect(httpsUrl, permanent: true);
        return;
    }

    // Add HSTS header
    context.Response.Headers.Add("Strict-Transport-Security", "max-age=31536000; includeSubDomains");

    await next();
});
```

**Method 3: Reverse Proxy (Nginx)**

Already shown in [Option 3](#option-3-reverse-proxy-nginxtraefik-with-tls-termination) above.

---

## Testing HTTPS

### 1. Health Check

```bash
curl https://mcp.example.com/health
```

Expected output:
```json
{
  "status": "Healthy",
  "service": "MCP Server",
  "timestamp": "2025-10-19T12:00:00Z"
}
```

### 2. MCP Invoke Endpoint

```bash
curl -X POST https://mcp.example.com/mcp/invoke \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your-api-key" \
  -d '{
    "jsonrpc": "2.0",
    "method": "tools/list",
    "id": "test-1"
  }'
```

### 3. TLS Configuration Check

```bash
# Check TLS version and cipher suite
nmap --script ssl-enum-ciphers -p 443 mcp.example.com

# Check certificate validity
echo | openssl s_client -connect mcp.example.com:443 -servername mcp.example.com 2>/dev/null | openssl x509 -noout -text
```

### 4. HSTS Validation

```bash
curl -I https://mcp.example.com/health | grep -i strict-transport-security
```

Expected output:
```
Strict-Transport-Security: max-age=31536000; includeSubDomains
```

### 5. SSL Labs Test

For public-facing servers, use [SSL Labs](https://www.ssllabs.com/ssltest/) to get an A+ rating.

---

## Troubleshooting

### Issue: "Unable to configure HTTPS endpoint"

**Symptom:**
```
Unhandled exception. System.InvalidOperationException: Unable to configure HTTPS endpoint.
```

**Solution:**
1. Verify certificate file exists at specified path
2. Check file permissions (readable by server process)
3. Verify password is correct
4. Check certificate format (must be PFX for Kestrel)

```bash
# Verify PFX file
openssl pkcs12 -info -in server.pfx -noout
```

### Issue: "The certificate chain was issued by an authority that is not trusted"

**Symptom:**
Clients reject the certificate as untrusted.

**Solution:**
1. Ensure CA bundle is included in PFX
2. Add intermediate certificates to certificate store
3. For development, use `dotnet dev-certs https --trust`

### Issue: "Connection reset" or "SSL handshake failed"

**Symptom:**
Client cannot establish TLS connection.

**Solution:**
1. Check firewall allows port 443
2. Verify TLS protocols match (client vs. server)
3. Check cipher suite compatibility

```bash
# Test with specific TLS version
openssl s_client -connect mcp.example.com:443 -tls1_2
```

### Issue: Certificate Expired

**Symptom:**
```
The remote certificate is invalid according to the validation procedure.
```

**Solution:**
1. Check certificate expiry:
   ```bash
   echo | openssl s_client -connect mcp.example.com:443 2>/dev/null | openssl x509 -noout -enddate
   ```
2. Renew certificate (see [Certificate Management](#certificate-management))
3. Deploy new certificate

### Issue: HSTS Not Working

**Symptom:**
Browser still allows HTTP connections.

**Solution:**
1. Verify HSTS header is sent:
   ```bash
   curl -I https://mcp.example.com/health | grep Strict-Transport-Security
   ```
2. Clear browser HSTS cache (Chrome: `chrome://net-internals/#hsts`)
3. Ensure middleware is configured correctly

---

## Production Checklist

Before deploying to production, verify:

- [ ] Valid TLS certificate from trusted CA
- [ ] Certificate includes full chain (intermediate + root)
- [ ] Private key is stored securely (Kubernetes secret, Azure Key Vault, etc.)
- [ ] Certificate password is stored in environment variable (not in config)
- [ ] Certificate expiry monitoring is configured
- [ ] Automatic renewal is set up (Let's Encrypt, certbot)
- [ ] HSTS header is enabled
- [ ] HTTP → HTTPS redirect is configured
- [ ] TLS 1.2+ is enforced (no SSLv3, TLS 1.0, TLS 1.1)
- [ ] Strong cipher suites are configured
- [ ] Certificate Common Name (CN) matches domain
- [ ] Firewall allows port 443
- [ ] Health check endpoint is accessible via HTTPS
- [ ] Load balancer (if used) is configured for TLS passthrough or termination
- [ ] Monitoring/alerting is set up for certificate expiry

---

## References

**ASP.NET Core Documentation:**
- [Configure HTTPS in Kestrel](https://learn.microsoft.com/en-us/aspnet/core/fundamentals/servers/kestrel/endpoints)
- [Enforce HTTPS](https://learn.microsoft.com/en-us/aspnet/core/security/enforcing-ssl)
- [HSTS Middleware](https://learn.microsoft.com/en-us/aspnet/core/security/enforcing-ssl#http-strict-transport-security-protocol-hsts)

**Security Best Practices:**
- [Mozilla SSL Configuration Generator](https://ssl-config.mozilla.org/)
- [OWASP TLS Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Transport_Layer_Protection_Cheat_Sheet.html)
- [SSL Labs Best Practices](https://github.com/ssllabs/research/wiki/SSL-and-TLS-Deployment-Best-Practices)

**Certificate Authorities:**
- [Let's Encrypt](https://letsencrypt.org/) - Free automated certificates
- [DigiCert](https://www.digicert.com/) - Commercial CA
- [Sectigo](https://sectigo.com/) - Commercial CA

---

**Document Version**: 1.0.0
**Last Updated**: 2025-10-19
**Maintained By**: Svrnty Development Team
**Related**: [Deployment Guide](deployment-guide.md), [Security Best Practices](../security/security-guide.md)