Конечно, ну за исключением виртуальных хостов и подключаемых конф. файлов - уверяю вас, там нет директивы keepalive_disable и нет никаких ссылок на значение "msie6".

#user nginx nginx;
user www www;
worker_processes 4;
worker_rlimit_nofile 131072;
worker_cpu_affinity 0001 0010 0100 1000;

error_log /var/log/nginx/error_log warn;

events {
worker_connections 65536;
use epoll;
# debug_connection 217.24.65.183;
}

http {
include /etc/nginx/mime.types;
default_type application/octet-stream;

log_format main
'$remote_addr - $remote_user [$time_local] '
'"$request" $status $bytes_sent '
'"$http_referer" "$http_user_agent" '
'"$gzip_ratio" $request_time';

client_header_timeout 10m;
client_body_timeout 10m;
send_timeout 10m;

client_max_body_size 700m;
connection_pool_size 256;
client_body_buffer_size 1024k;
client_header_buffer_size 8k;
large_client_header_buffers 4 8k;
request_pool_size 4k;

proxy_buffering on;
proxy_buffer_size 4k;
proxy_buffers 4096 4k;

open_file_cache max=2000 inactive=60s;
open_file_cache_valid 60;
open_log_file_cache max=1000 inactive=60s valid=1m;

geoip_country /usr/share/GeoIP/GeoIP.dat; # the country IP database
geoip_city    /usr/share/GeoIP/GeoLiteCity.dat; # the city IP database

gzip on;
gzip_min_length 1100;
gzip_buffers 4 8k;
gzip_types text/plain text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript;

output_buffers 1 128k;
postpone_output 1460;

aio on;
directio 512;
sendfile on;
tcp_nopush on;
tcp_nodelay on;

keepalive_timeout 75 20;
# keepalive_disable msie6;

ignore_invalid_headers on;
server_name_in_redirect on;

fastcgi_pass_request_headers on;
fastcgi_intercept_errors on;
fastcgi_buffer_size 32k;
fastcgi_buffers 8 16k;
fastcgi_read_timeout 300;
fastcgi_send_timeout 300;

# use the map module to correctly set $script_url variable
map $uri $script_url {
         ~^(?<script_filename>.+\.(php|html))(?<path_info>.+)$ $path_info;
         ~^(?<script_filename>.+\.(php|html))$ $script_filename;
}

index index.html;

upstream phpfarm {
 server unix:/var/run/fastcgi/php-fpm-1.sock weight=100 max_fails=3 fail_timeout=5;
 server unix:/var/run/fastcgi/php-fpm-2.sock weight=100 max_fails=3 fail_timeout=5;
 server unix:/var/run/fastcgi/php-fpm-3.sock weight=100 max_fails=3 fail_timeout=5;
       }

       # upload progress
       upload_progress uploads 1m;
       upload_progress_content_type "application/json";
       upload_progress_json_output;


### virtual host configuration

[...]

}