Пожалуйста:

server {
listen *:80;

error_page 403 404 = @fallback;
location @fallback {
proxy_pass http://127.0.0.1:81;
proxy_redirect off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}

error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /etc/nginx/html;
}

location / {
log_not_found off;
limit_req zone=one burst=10;
client_max_body_size 16m;
client_body_buffer_size 128k;
proxy_pass http://127.0.0.1:81/;
proxy_redirect off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_connect_timeout 90;
proxy_send_timeout 90;
proxy_read_timeout 90;
proxy_buffer_size 4k;
proxy_buffers 8 64k;
proxy_busy_buffers_size 64k;
proxy_temp_file_write_size 64k;
proxy_temp_path /var/tmp/nginx;
limit_except POST GET {
allow 92.181.34.42/32;
deny all;
}
}
location ~ /\.ht {
deny all;
}

location ~* \.(gif|jpg|jpeg|png|bmp|ico|js|css|txt|html|htm|xml|swf|flv)$ {
#root /var/www/servername1;
#expires 30d;
}
location ~* \.(mp3|wmv|avi|mpg|mpeg|mov|doc|pdf|rtf|xls|zip|rar)$ {
#root /var/www/servername1;
#expires 30d;
}
}