I'm runnning a default nginx package on Debian Bookworm. Normally I'm just using the HTTPS connections to that service and everything is fine. Default for HTTP port 80 is a redirect to the HTTPS protocol.
server {
listen 80 default_server;
listen [::]:80 default_server;
server_tokens off;
return 301 https://$host$request_uri;
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log error;
}
// vhosts with listen 443 configs omited here, they work
I've an IoT client, that doesnt speak HTTPS. So, I configured it to use HTTP to send sensor data to a hook url on the Nginx server. I added a VHost for that local domain xyz, that doesn't forward the request to HTTPS but processed it with plain HTTP.
server {
listen 80;
listen [::]:80;
server_name xyz;
server_tokens off;
location / {
root /var/www/html/;
}
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log error;
}
// vhosts with listen 443 configs omited here, they work
But that request is never processed by the Nginx.
Using curl, I'm getting this response
# curl -v http://localhost/
* Trying 127.0.0.1:80...
* Connected to localhost (127.0.0.1) port 80 (#0)
> GET / HTTP/1.1
> Host: localhost
> User-Agent: curl/7.88.1
> Accept: */*
>
* Received HTTP/0.9 when not allowed
* Closing connection 0
curl: (1) Received HTTP/0.9 when not allowed
(Info: Nginx is listening on all devices, no firewall is active, when I stop the service, the port is closed in Linux...).
There is no error log message neither in journald, nor in nginx access or error logs.
Then I tried hardcore telnet to port 80 and got a more strange result:
# telnet localhost 80
Trying ::1...
Connected to localhost.
Escape character is '^]'.
GET / HTTP/1.1
Connection closed by foreign host.
To be clear, I've entered GET / HTTP/1.1\n without a second empty line, only one "enter". When I enter something not HTTP conform, like a random string, the server responses with ??.
So, right after the first line, Nginx is closing the connection (the HTTP/0.9 response comes from curl itself).
Because I could not set the Host: header in the telnet request, this request never checks any virtual host configuration and I asume the curl client has the same issue. It tries to send all the headers to the socket, but the Nginx response is already there.
I don't have an idea, what is wrong. The server should at least wait for the Host-header before closing the connection. The /etc/nginx/nginx.conf is not changed.
According to nginx -t the configuration is ok, the server responses normal on curl -v https://localhost/. The SSL configuration etc. is omitted here. It's working.
