Remember to have a "catch-all" in your nginx configuration when using virtual domains

I got a bit stressed when I saw that a beta for a service I am working on was out in the open. I checked every config file and firewalls, and could not see why the site would respond to a different domain and the ip, when the server_name in nginx was set.

I cannot stress this enough: You need a catch-all in your nginx config!

If you do not have a server config block to catch all "none-virtual" domains, nginx just picks the first available configuration. Quite different from what I was used to with apache. And if you have private and public sites on a mixed box, that might be mission-critical if sensitive data gets out...

So do yourself a favor and throw this into your nginx config before the virtual hosts are loaded:

 server {
  root /usr/share/nginx/www;
  index index.html index.htm;

  location / {
    try_files $uri $uri/ /404.htm =404;
  }
 }


 ##
 # Virtual Host Configs
 ##
        # .... 

Without the above settings, your site will be accessible on any domain pointing to the server, and any IP the server hosts.

Nginx max length of server_names / server_names_hash_bucket_size

I have deployed quite a lot of sites lately, and since some of them have more than one alias, I tend to use the server_names attribute with more than one name

e.g. in /etc/nginx/sites-enables/mysite.conf

servernames somesite.example.com othersite.on.example2.com

This will throw the following error:

Starting nginx: nginx: [emerg] could not build the server_names_hash, you should increase server_names_hash_bucket_size: 32

To fix this, just increase the number in nginx.conf

server_names_hash_bucket_size 128;

Depending on how many sites you have as aliases, you might need the value to be higher or lower than 128