Здравствуйте.

Столкнулся с достаточно загадочной для меня ситуацией.

Ping сервера с выключенным nginx

icmp_req=9 ttl=61 time=0.652 ms

Через 3 минуты после старта nginx

icmp_req=129 ttl=61 time=229 ms


Сервер используется под хостинг wordpress
OS: Ubuntu 12.10

nginx.conf
user www-data;
worker_processes 4;
worker_rlimit_nofile 250000;
pid /var/run/nginx.pid;

events {
worker_connections 4096;
multi_accept on;
use epoll;
}

http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
server_names_hash_bucket_size 512;
reset_timedout_connection on;
resolver 127.0.0.1;
resolver_timeout 10s;

open_file_cache max=100000 inactive=40s;
open_file_cache_valid 60s;
open_file_cache_min_uses 2;
open_file_cache_errors on;

access_log off;
server_tokens off;
sendfile off;
tcp_nopush off;
keepalive_timeout 10;
tcp_nodelay off;
send_timeout 2;
gzip off;
client_header_buffer_size 4k;
large_client_header_buffers 8 8k;
output_buffers 32 512k;
sendfile_max_chunk 128k;
postpone_output 1460;

log_format main '$remote_addr - $remote_user [$time_local] $domain '
'"$request" $status $body_bytes_sent '
'"$http_referer" "$http_user_agent"';

include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}



Server-conf
server {
listen 80 default_server;

server_name ~^(www\.)?(?<domain>.+)$;

access_log /var/log/nginx/wp-access.log csv buffer=1m;
error_log /var/log/nginx/wp-error.log;

root /var/www/$domain;

index index.php;

location ~ \.(css|js|htc)$ {
access_log off;
log_not_found off;
}
location ~ \.(html|htm|rtf|rtx|svg|svgz|txt|xsd|xsl|xml)$ {
}

location = /favicon.ico { access_log off; log_not_found off; }
location = /robots.txt { access_log off; log_not_found off; }
location = /apple-touch-icon.png { access_log off; log_not_found off; }
location = /apple-touch-icon-precomposed.png { access_log off; log_not_found off; }

location = /wp-content {
access_log off;
expires max;
}
# Common deny or internal locations, to help prevent access to areas of
# the site that should not be public

location ~* wp-admin/includes { deny all; }
location ~* wp-includes/theme-compat/ { deny all; }
location ~* wp-includes/js/tinymce/langs/.*\.php { deny all; }

location /wp-includes/ { internal; }

location ~* wp-config.php { deny all; }

#location ~* ^/wp-content/uploads/.*.(html|htm|shtml|php)$ {
# types { }
# default_type text/plain;
#}

location ~ /\. { deny all; access_log off; log_not_found off; }

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

location ~ \.php$ {
fastcgi_pass php5-fpm-sock;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
proxy_ignore_client_abort on;
proxy_connect_timeout 120;
proxy_read_timeout 60;
proxy_send_timeout 60;
proxy_buffers 8 32k;
proxy_buffer_size 64k;
include /etc/nginx/fastcgi_params;
}
}

В логах nginx и syslog ничего аномального нет.

Подскажите, пожалуйста, с чем это может быть связанно и в какую сторону копать?

Заранее спасибо.