nginx default_site doesn't appear to be working - linux

Question

I've got nginx running in docker as a reverse proxy and have been for some time - and it works wonderfully, short of one little issue I've recently seen crop up.
What I'd like: when a user gets to my nginx server and there isn't a .conf file specified for the URL, either 404/444 or some other HTTP response that drops the connection.
What I'm seeing: when a user navigates to sudomain.url.com and that subdomain isn't specified in any of my *.conf files, nginx uses the first conf file it finds - ignoring the default.conf. Find my details below.
Any other tips/tricks you can provide would be awesome as well!
nginx.conf:
user nginx;
worker_processes 1;
error_log /etc/nginx/log/error.log warn;
pid /var/run/nginx.pid;
events {
worker_connections 1024;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /etc/nginx/log/access.log main;
sendfile on;
#tcp_nopush on;
keepalive_timeout 70;
#gzip on;
include /etc/nginx/conf.d/*.conf;
}
default.conf:
server {
server_name _;
listen 80 default_server;
return 444;
}
server {
server_name _;
listen 443 default_server;
return 444;
}
Example of a conf file (there are maybe a dozen of these):
server {
listen sub.domain.com:80;
server_name sub.domain.com;
return 302 https://sub.domain.com$request_uri;
}
server {
listen sub.domain.com:443;
server_name sub.domain.com;
ssl_certificate /etc/nginx/keys/ssl.pem;
ssl_certificate_key /etc/nginx/keys/ssl.key;
ssl on;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers 'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC4-SHA';
ssl_prefer_server_ciphers on;
ssl_dhparam /etc/nginx/keys/dhparams.pem;
add_header X-Frame-Options SAMEORIGIN;
add_header X-XSS-Protection "1; mode=block";
add_header Strict-Transport-Security "max-age=31536000; includeSubdomains";
location / {
proxy_pass http://10.0.1.4:81;
proxy_buffering off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
}

Answer 1

I haven't actually tested this but my gut feeling is that your listen directives shouldn't contain a host name. They should contain the IP address of the interface you want to be listening on and the port you want to be listening to. Then for each different port/IP combination you can specify one of them as the default.
Only after resolving which IP address did the request go to and which port was it on, nginx begins to actually process the request. The first step here is to check the Host header, if it finds a matching server block for the value of the host header then that's where it should route. If it doesn't find one then it should route to the default.
If there is no host header being received then, I think, in more recent versions of nginx it will drop the request, however it would previously just handle this by sending to the default server for the IP/port combo.
Below is an nginx.conf which gives me working endpoints for named servers and returns 404 for everything else. Due to HSTS headers you need to hit test.se{1,2,3,4}.home-v.ind.in to see it work or you will just get back a browser error.
user nginx;
worker_processes auto;
error_log stderr notice;
pid /var/run/nginx.pid;
events {
worker_connections 1024;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
sendfile on;
tcp_nopush on;
keepalive_timeout 300s;
ssl_certificate /etc/pki/nginx/fullchain.pem;
ssl_certificate_key /etc/pki/nginx/privkey.pem;
ssl_dhparam /etc/pki/nginx/dhparams.pem;
ssl_protocols TLSv1.2;
ssl_ciphers EECDH+CHACHA20:EECDH+AES128:RSA+AES128:EECDH+AES256:RSA+AES256:EECDH+3DES:RSA+3DES:!MD5;
ssl_prefer_server_ciphers on;
ssl_buffer_size 1400;
ssl_session_timeout 1d;
ssl_session_cache shared:SSL:50m;
ssl_stapling on;
ssl_stapling_verify on;
ssl_trusted_certificate /etc/pki/nginx/fullchain.pem;
add_header "Cache-Control" "no-transform";
add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;
resolver 8.8.8.8 8.8.4.4 216.146.35.35 216.146.36.36 valid=60s;
resolver_timeout 2s;
server {
listen 80 default_server;
server_name _;
return 301 https://$host$request_uri;
}
server {
listen 443 ssl http2;
server_name test.se1.home-v.ind.in;
root /usr/share/nginx/html;
location /.well-known { satisfy any; allow all; try_files $uri $uri/ =404; }
location /robots.txt { satisfy any; allow all; add_header Content-Type text/plain; return 200 "User-agent: *\nDisallow: /\n"; }
location / { satisfy any; allow all; add_header Content-Type text/plain; return 200 "Test Site 1"; }
}
server {
listen 443 ssl http2;
server_name test.se2.home-v.ind.in;
root /usr/share/nginx/html;
location /.well-known { satisfy any; allow all; try_files $uri $uri/ =404; }
location /robots.txt { satisfy any; allow all; add_header Content-Type text/plain; return 200 "User-agent: *\nDisallow: /\n"; }
location / { satisfy any; allow all; add_header Content-Type text/plain; return 200 "Test Site 2"; }
}
server {
listen 443 ssl http2 default_server;
server_name _;
root /usr/share/nginx/html;
location /.well-known { satisfy any; allow all; try_files $uri $uri/ =404; }
location / { return 404; }
}
}