HTTPS Redirection - when HTTP request has made to AIO - Apache

[surapuramakhil]

Steps to reproduce

1. AIO Setup (reverse proxy setup)
2. Run Next Cloud - using AIO
3. make https request to Apache gateway container (11000) port

Expected behavior

either do http redirection, as HTTPS is not supported by current AIO Apache gateway container

or

bare minimum - return a 4xx error, which error message HTTPS not supported.

Actual behavior

Server won't respond, at least No Error message provided

Other information

Host OS

Output of sudo docker info

Docker run command or docker-compose file that you used

Other valuable info

[szaimen]

either do http redirection, as HTTPS is not supported by current AIO Apache gateway container

or

bare minimum - return a 4xx error, which error message HTTPS not supported.

I honestly don't know how we can achieve any of this using this Caddyfile: https://github.com/nextcloud/all-in-one/blob/main/Containers/apache/Caddyfile. Any idea on the topic is welcome.

---

Btw, I dont know where you got the idea to point at the APACHE_PORT using https? This was nowhere documented, always http was used, no?

[surapuramakhil]

where you got the idea to point at the APACHE_PORT using https

because AIO runs on https, even if it is behind proxy.

[Zoey2936]

this request should be sent to caddy, but not even nginx support something like this

[surapuramakhil]

@Zoey2936 there are way to do achieve this

my AI conversations - looks like its responses are reasonable and doable - default behaviour is connection closed (assumption of SSL error) (this might not even seen do downstream , reverse proxy send 502 error)

---

apache, caddy, nginx rejecting https request to specific port - respond 4xx with reponse "sent https request, send http instead"

--

When Apache, Caddy, or Nginx rejects HTTPS requests on a specific port with a 4xx error like "sent HTTPS request, send HTTP instead," it typically indicates a protocol mismatch or misconfiguration. Below is a breakdown of potential causes and solutions for each server, based on the provided search results and general troubleshooting practices:

---

1. Apache Configuration Issues

• Port Typo or Misbinding: In [webpage 1], the user mistakenly configured Apache's secure VirtualHost to listen on port *:433 instead of *:443. This caused Apache to treat HTTPS traffic on port 443 as plain HTTP, leading to SSL protocol errors (e.g., ERR_SSL_PROTOCOL_ERROR).
  • Fix: Ensure the <VirtualHost> directive uses *:443 and that Listen 443 is enabled in ports.conf or apache2.conf.
• SSL Module Not Enabled: If mod_ssl is not loaded, Apache cannot process HTTPS requests. Verify with a2enmod ssl and restart Apache.
• Incomplete SSL Directives: Missing SSLEngine on, incorrect certificate paths (e.g., SSLCertificateFile), or commented-out SSL configurations (e.g., #<IfModule mod_ssl.c>) can cause failures.

---

2. Nginx Configuration Issues

• Missing SSL Directives: If a server block lacks listen 443 ssl; and ssl_certificate/ssl_certificate_key declarations, Nginx defaults to HTTP on port 443, rejecting HTTPS requests with protocol errors.
• Port-Protocol Mismatch: Binding a non-SSL server block to port 443 (e.g., listen 443; without ssl) forces HTTP-only communication, triggering errors when HTTPS is used.

---

3. Caddy Configuration Issues

• Automatic HTTPS Misconfiguration: Caddy defaults to automatic HTTPS on port 443. If a custom port is used (e.g., :8443), explicitly define TLS in the Caddyfile:

  example.com:8443 {
      tls /path/to/cert.pem /path/to/key.pem
      respond "HTTPS active"
  }
  

• HTTP-Only Port Binding: If Caddy is configured without TLS on a specific port, it will reject HTTPS requests. Ensure TLS settings align with the intended port.

---

Common Root Causes Across Servers

1. Port-Protocol Mismatch: Servers expect HTTP on non-standard ports unless explicitly configured for HTTPS. For example, using http://example.com:443 worked in [webpage 1] because Apache treated it as HTTP, but HTTPS failed due to SSL misconfiguration.
2. Certificate Issues: Invalid, expired, or misconfigured SSL certificates (e.g., incorrect file permissions or paths) prevent TLS handshakes.
3. Firewall/Network Restrictions: Port blocking or SSL termination at a load balancer might force HTTP instead of HTTPS.

---

Testing and Debugging Steps

1. Verify Listening Ports: Use netstat -tupln or ss -tuln to confirm the server is bound to 0.0.0.0:443 (Apache/Nginx) or the correct custom port (Caddy).
2. Check Server Logs:
   • Apache: Review error.log for AH00566 or SSL initialization errors.
   • Nginx/Caddy: Look for SSL_do_handshake() failures or protocol mismatches.
3. Test with curl:

   curl -vk https://example.com:443  # Check SSL handshake
   curl -v http://example.com:443    # Test HTTP on HTTPS port

---

Summary of Fixes

Server	Action Items
Apache	Correct port to 443, enable mod_ssl, validate certificate paths.
Nginx	Add listen 443 ssl; and SSL certificate directives.
Caddy	Explicitly define TLS for non-standard ports.

For persistent issues, ensure the server is reloaded after configuration changes (e.g., systemctl reload apache2). If the problem involves third-party tools (e.g., Next.js dev servers), consider reverse proxies or experimental HTTPS flags as discussed in [webpage 2].

---

okay how about this way? ah https request made to port 80, reverse proxy instead of dropping request, saying you shoud make http instead

---

To configure a reverse proxy (Nginx, Apache, Caddy) to respond to HTTPS requests on port 80 with a 4xx error and a message like "sent HTTPS request, send HTTP instead" instead of dropping the connection, use the following approaches:

---

1. Nginx Configuration

Nginx can detect SSL/TLS handshakes on port 80 using the ssl_reject_handshake directive (requires Nginx 1.19.4+). This allows it to reject HTTPS requests with a custom response:

# Respond to HTTPS requests on port 80
server {
    listen 80 ssl;  # Enable SSL context for port 80
    ssl_reject_handshake on;  # Reject SSL handshake but respond in plain HTTP
    return 400 'sent HTTPS request, send HTTP instead';
}

# Normal HTTP server for port 80
server {
    listen 80;
    server_name example.com;
    # Proxy or serve content for legitimate HTTP requests
    location / {
        proxy_pass http://backend;
    }
}

How it works:

• The first server block listens on port 80 with SSL enabled but rejects handshakes.
• Clients sending HTTPS requests to port 80 receive a plain HTTP 400 Bad Request response.
• Legitimate HTTP traffic is handled by the second server block.

---

2. Apache Configuration

Apache can use a "dummy" SSL setup on port 80 to force an error, then customize the error response:

Listen 80
<VirtualHost *:80>
    # Enable SSL to trigger a handshake failure
    SSLEngine on
    SSLCertificateFile /path/to/dummy.crt
    SSLCertificateKeyFile /path/to/dummy.key

    # Custom error response for SSL failures
    ErrorDocument 400 "sent HTTPS request, send HTTP instead"

    # Force a 400 error if SSL is detected
    RewriteEngine On
    RewriteCond %{SSL_PROTOCOL} !^$ [NC]
    RewriteRule ^ - [R=400]
</VirtualHost>

# Normal HTTP handling (optional)
<VirtualHost *:80>
    ServerName example.com
    # Proxy or serve content for HTTP requests
    ProxyPass "/" "http://backend/"
</VirtualHost>

Notes:

• Replace /path/to/dummy.crt and /path/to/dummy.key with placeholder certificates (generate self-signed ones if needed).
• The RewriteCond checks for SSL negotiation and triggers a 400 response.
• This method is less clean than Nginx’s approach but works for legacy systems.

---

3. Caddy Configuration

Caddy automatically handles HTTPS, but you can explicitly disable TLS on port 80 and add a responder for HTTPS detection:

example.com:80 {
    # Detect HTTPS requests (not straightforward in Caddy)
    @malformed_https {
        protocol https
    }
    respond @malformed_https 400 "sent HTTPS request, send HTTP instead"

    # Handle normal HTTP traffic
    respond "Hello, this is HTTP!" 200
}

Limitations:

• Caddy may not reliably detect HTTPS on port 80 because it expects TLS on port 443 by default.
• This workaround uses the protocol matcher, but it may not catch all cases (e.g., clients sending TLS on port 80).

---

Testing with curl

Verify the setup by sending HTTPS requests to port 80:

# Test HTTPS to port 80 (expect a 400 error)
curl -k -v https://example.com:80

# Test HTTP to port 80 (expect normal response)
curl -v http://example.com:80

---

Key Takeaways

• Nginx: Cleanest solution using ssl_reject_handshake.
• Apache: Requires dummy certificates and rewrite rules.
• Caddy: Limited native support; detection may not be reliable.
• Always test configurations and check server logs for errors (e.g., nginx -t, apachectl configtest).

---

can you confirm default behaviour when you don't do this

---

A 502 Bad Gateway error in Nginx when acting as a reverse proxy to an HTTP backend typically indicates that Nginx cannot communicate properly with the upstream server (your HTTP service). Here’s a breakdown of common causes and solutions:

---

1. Backend Service Not Running or Unreachable

• Check if the backend service is running:

  curl -v http://localhost:YOUR_BACKEND_PORT  # Replace with your actual port

  If this fails, your backend service (e.g., Node.js, Python, etc.) is not running or not listening on the configured port.

• Verify the service is binding to the correct interface:

  • If your backend is bound to 127.0.0.1 (localhost), ensure Nginx is on the same machine.
  • If Nginx is in a Docker container or separate server, bind the backend to 0.0.0.0 to allow external connections.

---

2. Nginx Configuration Errors

Misconfigured proxy_pass

Ensure the proxy_pass directive points to the correct backend URL and port:

location / {
    proxy_pass http://localhost:3000;  # Example: Proxy to a Node.js app on port 3000
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}

• If the backend is on a different machine, replace localhost with the server’s IP or DNS name.
• If using Docker, use the service name (e.g., http://backend-app:3000).

Missing Headers

Add essential headers to avoid backend errors:

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;

---

3. Firewall or Network Issues

• Check firewall rules blocking traffic between Nginx and the backend:

  sudo ufw status  # Check if the backend port is allowed

• Test connectivity from the Nginx server to the backend:

  telnet localhost 3000  # Replace with your backend port

  If this fails, the backend isn’t reachable (e.g., not running, blocked by firewall, or misconfigured binding).

---

4. Backend Crashes or Timeouts

• Check backend logs for crashes or errors:

  journalctl -u your-backend-service  # Systemd services

• Adjust Nginx timeouts if the backend is slow to respond:

  proxy_connect_timeout 60s;
  proxy_read_timeout 60s;
  proxy_send_timeout 60s;

---

5. DNS Resolution Issues (If Using Hostnames)

If your proxy_pass uses a hostname (e.g., http://backend-service:3000), ensure Nginx can resolve it:

# Test DNS resolution from the Nginx server
nslookup backend-service

---

6. Port Conflicts

Ensure no other service is using the backend port:

sudo lsof -i :3000  # Replace with your backend port
sudo netstat -tuln | grep :3000

---

Debugging Steps

1. Check Nginx Error Logs:

   tail -f /var/log/nginx/error.log  # Look for "connection refused" or "timed out"

   Common errors:

   connect() failed (111: Connection refused) while connecting to upstream
   upstream timed out (110: Connection timed out)
   

2. Test the Backend Directly:

   curl http://localhost:3000  # Replace with your backend port

   If this works, the issue is likely in Nginx’s configuration or network setup.

3. Test Nginx-to-Backend Connectivity:
   From the Nginx server, run:

   curl http://backend-ip:backend-port

---

Example Fix

Symptom:
502 Bad Gateway with Nginx logs showing connection refused.

Cause:
Backend service not running or bound to 127.0.0.1 while Nginx is in a Docker container.

Solution:

• Bind the backend to 0.0.0.0:3000 (not localhost:3000).
• Update proxy_pass to use the Docker host IP or service name:

  proxy_pass http://host.docker.internal:3000;  # For Docker-to-host communication

---

Summary

• Most 502 errors stem from Nginx being unable to reach the backend.
• Start by verifying the backend is running, accessible, and not blocked by firewalls.
• Check Nginx’s proxy_pass configuration and error logs for clues.
• Adjust timeouts and headers if the backend is slow or misconfigured.

[Zoey2936]

your nginx example won't even work without setting a tls cert...

[szaimen]

this request should be sent to caddy, but not even nginx support something like this

Thanks for the feedback Zoey! Closing then 👍

@surapuramakhil please send a feature request to caddy server.

[surapuramakhil]

@szaimen @Zoey2936

But maybe we could clarify in the reverse proxy guide that it runs on http not https

Agreed.

it would be much better sending error responses (it would be very helpful) by the way I already fixed, its only helpful for next person who is setting up nextcloud

[surapuramakhil]

TLDR @Zoey2936 it's doable in any reverse proxy

[Zoey2936]

no, in nginx you would need to use a stream server to inspect the package and then decide to use http or https as backend, in caddy this is not possible: caddyserver/caddy#3687

[surapuramakhil]

I guess updating docs is the way then 😅

[Zoey2936]

see #5979