5. Deploy with Reverse Proxy

5.1. Reverse Proxy or Kubernetes Ingress Controller for mTLS/CAC Authentication

STIG Manager supports native TLS connections without requiring a reverse proxy. You can configure HTTPS directly in the application using environment variables. See the Environment Variables beginning with STIGMAN_API_TLS_* in the documentation for details on enabling native TLS.

A reverse proxy or Kubernetes Ingress Controller is still required for:

• mTLS (Mutual TLS) for client certificate authentication (ie. CAC/PIV)

• Environmental requirements such as centralized TLS termination, load balancing, or security policies

• Additional proxy features like request filtering, rate limiting, or advanced routing

If you need a reverse proxy, configure it (such as nginx) or your Kubernetes Ingress Controller in accordance with publisher documentation, local security requirements, and OIDC Provider (eg. Keycloak) documentation.

Keycloak Configuration for Reverse Proxy Environments:

• Keycloak 26+: Set KC_PROXY_HEADERS=xforwarded and KC_HTTP_ENABLED=true (if TLS terminates at proxy)

• Ensure your proxy forwards appropriate headers (X-Forwarded-For, X-Forwarded-Proto, X-Forwarded-Host)

The STIG Manager OSS team provides a repository on GitHub with a sample nginx deployment, with a configuration file that may be useful to those setting up a Production deployment:

https://github.com/NUWCDIVNPT/stigman-orchestration

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Component Diagram with Reverse Proxy

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Component Diagram with Kubernetes

5.2. Proxy Configuration

Proxy configuration will vary greatly depending on your environment, desired network structure, and choice of reverse proxy software. Below are some general guidelines and considerations when configuring your reverse proxy for use with STIG Manager.

5.2.1. Max Request Body Size

Some proxies such as nginx may have default limits on request body size that are quite small (e.g. 5MB). You will likely need to increase this limit using the appropriate directive (e.g. client_max_body_size 100M; in nginx). A 100MB limit is a reasonable starting point.

5.2.2. Proxy Requirements for Streaming, SSE, and WebSocket Endpoints

Important

STIG Manager uses streaming responses, Server-Sent Events (SSE), and WebSocket connections for real-time operations. These may require specific proxy configuration to function properly.

For proper operation of streaming, SSE, and WebSocket endpoints, your proxy must:

1. Disable response buffering for streaming endpoints

2. Pass through streaming headers without modification

3. Maintain persistent connections for SSE and WebSocket endpoints

4. Support HTTP connection upgrade for WebSocket endpoints

The application automatically sets the x-accel-buffering: no header which nginx (and Azure Application Gateway) honors by default to disable buffering. Other proxies may require explicit configuration.

Warning

If your proxy is configured to:

• Override or ignore response headers

• Force buffering on all responses

• Have aggressive timeout settings for long-lived connections

You MUST adjust your proxy configuration to exempt the endpoints listed below.

5.2.3. Essential Streaming Endpoints

The following endpoints require unbuffered, real-time response streaming:

Streaming Responses (NDJSON):

• POST /collections/{collectionId}/export-to/{dstCollectionId}

  • Content-Type: application/x-ndjson

  • Operation: Collection export with progress updates

  • API operationId: exportToCollection

• POST /collections/{collectionId}/clone

  • Content-Type: application/x-ndjson

  • Operation: Collection cloning with progress updates

  • API operationId: cloneCollection

Server-Sent Events (SSE):

• GET /op/state/sse

  • Content-Type: text/event-stream

  • Operation: Real-time operation state updates

  • API operationId: streamStateSse

WebSocket Connection:

• GET <origin>/socket/log-socket

  • Requires HTTP connection upgrade to WebSocket protocol

  • Operation: Real-time log streaming over WebSocket

5.2.4. Proxy-Specific Configuration Examples

While specific configuration varies by proxy, here are the key settings to verify:

nginx:

• Honors x-accel-buffering: no header automatically (no configuration needed)

• Ensure proxy_buffering is not forced to on globally

• Add support for WebSockets in stigman location block:

  proxy_http_version      1.1;
  proxy_set_header        Upgrade $http_upgrade;
  proxy_set_header        Connection "upgrade";
  proxy_set_header        Host $host;
  proxy_read_timeout      3600s;  # Also affects SSE connections
  

Apache (mod_proxy_http):

• Basic ProxyPass with HTTP backends typically works for SSE

• Use ProxyPreserveHost On for proper host header forwarding

• If issues occur, may need to adjust Keep-Alive or timeout settings for SSE endpoints

HAProxy:

• Typically works without modification

• Verify timeout server and timeout client for long connections

Other Proxies:

• Most modern proxies automatically detect and handle SSE (Content-Type: text/event-stream)

• Consult proxy documentation for buffering and timeout configuration if issues occur

5.2.5. Verifying Proper Configuration

Test SSE Endpoint:

After deployment, test the SSE endpoint to verify proper streaming:

curl -N http://<api-url>/op/state/sse

Or open in a browser:

http://<api-url>/op/state/sse

Expected behavior:

• Immediate initial response (within 1-2 seconds)

• Periodic keepalive events every 30 seconds

• No long delay before first response

If issues occur:

• Long delay before any response → Proxy is buffering

• Connection drops after timeout → Timeout settings too aggressive

• No events received → Headers being stripped or modified

5.2.6. Troubleshooting Option

If you experience persistent buffering issues that cannot be resolved through proxy configuration, STIG Manager provides an environment variable to temporarily disable SSE functionality:

STIGMAN_CLIENT_STATE_EVENTS=false

This disables the web client’s SSE listening for API state events. This should only be used temporarily while resolving proxy buffering issues, as it disables real-time operation monitoring.