nginx $server_name is always localhost

Question

I have an nginx 1.4.5 server running on an AWS EC2 instance. I have two conf file: the default.conf and myapp.conf. The default.conf listen to localhost, and myapp.conf listen to myapp.mydomain.com.

However I found even I type in myapp.mydomain.com in the browser, it always load the default.conf. I've changed the log_format in nginx.conf file add a "$server_name" field to check the server name of each request. I found it's always localhost.

Any one has any idea about this?

Updates with configuration info

the nginx.conf

server {
     listen       80;
     server_name  localhost;

     #charset koi8-r;
     #access_log  /var/log/nginx/log/host.access.log  main;

     location / {
         root   /usr/share/nginx/html;
         index  index.html index.htm;
     }
...
}

The myapp.conf

 server {
     listen 80;
     server_name myapp.mydomain.com;

     access_log /var/log/nginx/myapp.log;

     location / {
         add_header P3P 'CP="CAO PSA OUR"';
         proxy_pass http://127.0.0.1:8080/myapp/;
         set $ssl off;
         if ($scheme = https) {
             set $ssl on;
         }
         proxy_set_header X-Forwarded-Ssl $ssl;
         proxy_set_header Host $host;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header X-Real-IP $remote_addr;
     }
 }

And yes I am behind two firewalls, one is iptable, the other one is AWS built in secure group

Answer 1

Someone with a similar problem got it fixed by:

I've fixed this now, in case anyone has the same problem as me it was to do with "server_names_hash_bucket_size 64;" in /etc/nginx/nginx.conf.

That line was commented out by default so I uncommented and restarted nginx and it works fine now.