Changing the default port of nginx

i recently installed nginx on raspberry in order to host a wordpress site.Everything is going fine so far and i can see my wordpress site,but i have stumbled upon a major issue.I need to change the default port which is 80 to something else,since my dlink nas currently uses this port.

Tried editing /etc/nginx/sites-enabled/default
specifically the line which says
listen to 80 to listen to 100 inside the server block.
I save the file restart,but nothing happens i can no longer even log into the wordpress site.If i change it back to 80 i can log into the page via my browser just fine once again.

Anyway this is the current code of the default file.Any assistance would be greatly appreciated.

The code below only works when i set the port back to 80,any other port fails,including the 100 port you see here.Everything i tried is on the local network.

# You may add here your
# server {
#   ...
# }
# statements for each of your virtual hosts to this file

##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

server {
   listen  100; ## listen for ipv4; this line is default and implied
   root /usr/share/nginx/www;
   index index.php index.html index.htm ;

   # Make site accessible from http://localhost/
   server_name localhost;

   location / {
      # First attempt to serve request as file, then
      # as directory, then fall back to displaying a 404.
      try_files $uri $uri/ /index.php;
      # Uncomment to enable naxsi on this location
      # include /etc/nginx/naxsi.rules
   }

   location /doc/ {
      alias /usr/share/doc/;
      autoindex on;
      allow 127.0.0.1;
      allow ::1;
      deny all;
   }

   # Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests
   #location /RequestDenied {
   #   proxy_pass http://127.0.0.1:8080;   
   #}

   #error_page 404 /404.html;

   # redirect server error pages to the static page /50x.html
   #
   #error_page 500 502 503 504 /50x.html;
   #location = /50x.html {
   #   root /usr/share/nginx/www;
   #}

   # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
   #
   location ~ .php$ {
   fastcgi_split_path_info ^(.+.php)(/.+)$;
   #   # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini

   #   # With php5-cgi alone:
   #   fastcgi_pass 127.0.0.1:9000;
   #   # With php5-fpm:
   fastcgi_pass unix:/var/run/php5-fpm.sock;
   fastcgi_index index.php;
   include fastcgi_params;
   }

   # deny access to .htaccess files, if Apache's document root
   # concurs with nginx's one
   #
   #location ~ /.ht {
   #   deny all;
   #}
}


# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
#   listen 8000;
#   listen somename:8080;
#   server_name somename alias another.alias;
#   root html;
#   index index.html index.htm;
#
#   location / {
#      try_files $uri $uri/ =404;
#   }
#}


# HTTPS server
#
#server {
#   listen 443;
#   server_name localhost;
#
#   root html;
#   index index.html index.htm;
#
#   ssl on;
#   ssl_certificate cert.pem;
#   ssl_certificate_key cert.key;
#
#   ssl_session_timeout 5m;
#
#   ssl_protocols SSLv3 TLSv1;
#   ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv3:+EXP;
#   ssl_prefer_server_ciphers on;
#
#   location / {
#      try_files $uri $uri/ =404;
#   }
#}