NGINX not respecting server_name regex - nginx-config

Question

I have this nginx config.. i want it to accept all domains that have the word competitions in it and end with .com.au.. I have tested with a domain name that should NOT be accepted but it reaches the application.. is the server_name being ignore because I'm using a proxy?
server {
listen 80 default_server;
server_name ~^(.+)competitions?(.+)\.com\.au;
access_log /var/log/nginx/$host.access.log;
error_log /var/log/nginx/error.log;
if ($host !~* ^www){
rewrite ^/(.*)$ https://www.$host/$1 permanent;
}
location / {
proxy_no_cache 1;
proxy_set_header Host $host;
proxy_pass http://127.0.0.1:8888;
try_files $uri $uri/ #proxy;
}
location #proxy {
proxy_set_header Host $host;
proxy_pass http://127.0.0.1:8888;
proxy_intercept_errors on;
recursive_error_pages on;
error_page 404 = #rewrite_proxy;
}
location #rewrite_proxy {
rewrite /(.*) /index.cfm?path=$1;
proxy_set_header Host $host;
proxy_pass http://127.0.0.1:8888;
}
}

Answer 1

You'd have to remove the default_server from there, because this is a catch-all directive.And you still could setup another one server with the default_server directive, if required.
See How nginx processes a request for a more detailed explanation:
If its value does not match any server name, or the request does not contain this header field at all, then nginx will route the request to the default server for this port.