вот конфиги. Они у меня разнесены по файлам. В файле /etc/nginx/sites-enabled/reset.conf отдельно расположены конфиг запрета запроса сайта по ip.
Надеюсь, это что-то даст.

#### /etc/nginx/nginx.conf

user www-data;
worker_processes 8;

error_log /var/log/nginx/error.log notice;

pid /var/run/nginx.pid;
worker_rlimit_nofile 8192;
timer_resolution 100ms;
worker_priority -5;

events {
worker_connections 2048;
use epoll;
}


http {
include 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 logs/access.log main;
index index.php index.html index.htm;

sendfile on;
#tcp_nopush on;

#keepalive_timeout 0;
keepalive_timeout 65;
client_max_body_size 20m;

gzip on;
gzip_static on;
gzip_min_length 1000;
gzip_proxied any;
gzip_types text/plain text/xml application/xml application/x-javascript text/javascript text/css text/json;
gzip_disable "msie6";
gzip_comp_level 8;


include /etc/nginx/sites-enabled/*;
}


### /etc/nginx/sites-enabled/site1.conf
server {
listen 192.168.10.1:80;
server_name example1.com;
access_log /home/example1.com/logs/access.log main;

charset windows-1251;

root /home/example1.com/www;

error_page 404 /index.php;

location ~* \.(js|JPG|jpg|png|jpeg|gif|zip|tgz|gz|rar|doc|xls|exe|pdf|ppt|txt|wav|bmp|rtf)$ {
expires 1y;
open_file_cache_errors off;
# error_page 404 = @fetch;
access_log off;
}

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

location / {
try_files $uri $uri/ /index.php?$args;
}

# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
location ~ \.php$ {
try_files $uri =404;

fastcgi_split_path_info ^(.+\.php)(/.+)$;
include fastcgi_params;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
# fastcgi_intercept_errors on;
fastcgi_pass 127.0.0.1:9000;
}
}



### /etc/nginx/sites-enabled/site2.conf
server {
listen 192.169.10.2:80;
server_name example2.com;
access_log /home/example2.com/logs/access.log main;

charset utf8;

root /home/example2.com/www;

error_page 404 /index.php;

location ~* \.(js|JPG|jpg|png|jpeg|gif|zip|tgz|gz|rar|doc|xls|exe|pdf|ppt|txt|wav|bmp|rtf)$ {
expires 1y;
open_file_cache_errors off;
# error_page 404 = @fetch;
access_log off;
}

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

location / {
try_files $uri $uri/ /index.php?$args;
}

# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
location ~ \.php$ {
try_files $uri =404;

fastcgi_split_path_info ^(.+\.php)(/.+)$;
include fastcgi_params;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
# fastcgi_intercept_errors on;
fastcgi_pass 127.0.0.1:9000;
}


}



### /etc/nginx/sites-enabled/site3.conf
server {
listen 192.169.10.3:80;
server_name example3.com;
access_log /home/example3.com/logs/access.log main;

charset utf8;

root /home/example3.com/www;

error_page 404 /index.php;

location ~* \.(js|JPG|jpg|png|jpeg|gif|zip|tgz|gz|rar|doc|xls|exe|pdf|ppt|txt|wav|bmp|rtf)$ {
expires 1y;
open_file_cache_errors off;
# error_page 404 = @fetch;
access_log off;
}

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

location / {
try_files $uri $uri/ /index.php?$args;
}

# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
location ~ \.php$ {
try_files $uri =404;

fastcgi_split_path_info ^(.+\.php)(/.+)$;
include fastcgi_params;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
# fastcgi_intercept_errors on;
fastcgi_pass 127.0.0.1:9000;
}


}


### /etc/nginx/sites-enabled/reset.conf
server {
listen 192.168.10.1 default_server;
server_name _;
access_log off;
return 444;
}

server {
listen 192.168.10.2 default_server;
server_name _;
access_log off;
return 444;
}
server {
listen 192.168.10.3 default_server;
server_name _;
access_log off;
return 444;
}