Squid autenticado deixando a internet lenta do nada

Esta com o squid funcionando normal em uma máquina com o ubuntu 12.04 e outro em um CentOS virtualizado. Do nada na maquina com ubuntu a internet só estava funcionando o site do IG. Então fui testar a internet em uma máquina que não passa pelo proxy e a mesma está normal.

Peguei as conf e joguei em o proxy e deixei as mesmas configurações em outro centos que tenho virtualizado e o problema continua. Quando marco o squid para o usuário autenticar, ele demora muito para abrir um site. Quando tiro a máquina do proxy, ela navega super rápido. O engraçado, é que não mudei nada e já vinha rodando a mais de 6 meses assim. Abaixo coloco o squid.conf e se algúém puder me ajudar pois como já troquei até de SO, não sei mais o que fazer.

#NOME DO SERVIDOR#####################################################
visible_hostname ubuntuserver

######################################################################
#IP+PORTA USADA ####################################################
http_port 10.0.1.254:3128
######################################################################
icp_port 0
######################################################################
#CACHE USADO-METADE DA RAM)###########################################
cache_mem 256 MB
######################################################################
#Cache Swap###########################################################
cache_swap_low 80
cache_swap_high 90
######################################################################
#OBJECT_SIZE##########################################################
maximum_object_size 200 MB
minimum_object_size 0 KB
#tamanho máximo dos objetos alocados na memória.
maximum_object_size_in_memory 30 KB
######################################################################
#DIRETORIOS DO CACHE MULTIPLOS########################################
cache_dir aufs /var/cachesquid1 5000 16 256

#Erro squid
error_directory /usr/share/squid/errors/pt-br/

# Resolve um problema com conexões persistentes que ocorre com certos servidores,
# e que provoca delays em nosso cache.
detect_broken_pconn on

# Provoca um ganho de performance ao usar conexões Pipeline (requisições em
# paralelo)
#pipeline_prefetch on

#DNS squid cache
#dns_nameservers 10.0.1.254
#dns_nameservers 127.0.0.1

#####################################################################
#LOGS################################################################
cache_access_log /var/log/squid/access.log
cache_log /var/log/squid/cache.log
cache_store_log none
#####################################################################
#REGRA AUTENTICACAO
auth_param basic program /usr/lib/squid/ncsa_auth /etc/squid/passwd
auth_param basic children 5
auth_param basic realm Digite seu usuario e senha
auth_param basic credentialsttl 2 hours
auth_param basic casesensitive off
####################################################################
request_body_max_size 0 MB
####################################################################

#ACL's########################################################
#SITES QUE NÃO PRECISAM DE AUTENTICACAO COM SENHA
acl NO_AUTH url_regex -i '/etc/squid/no_auth_url'
http_access allow NO_AUTH
#################################################
#SITES BLOQUEADOS PARA QUALQUER USUARIO
acl BLOCK url_regex -i '/etc/squid/bloqueados'
http_access deny BLOCK

#################################################
#MSN SÓ PARA USUARIOS DESSA ACL##################
acl bloqueiamsn url_regex -i "/etc/squid/bloqueiamsn"
acl g_liberado proxy_auth inspetor inspetornfa wellington barbara alisson neide ademario marinalva fernando rmartins vicente handerson
http_access deny bloqueiamsn !g_liberado
#################################################
##### BLOQUEIO DE DOWNLOAD DAS EXTENSOES ABAIXO##
acl extensoes url_regex -i \.bat \.scr \.mp3 \.bat \.vbs \.wmv \.wma \.mp4
http_access deny extensoes

#acl downloads urlpath_regex "/etc/squid/downloads.txt"
#http_access deny downloads
#testando a opcao abaixo
#acl downloads req_mime_type application/octet-stream application/zip audio/mpeg audio/wav video/mpeg video/avi video/quicktime video/x-msvideo video/x-ms-wmv/
#http_access deny downloads
#################################################
#REGRAS GERAIS###################################
acl localnet src 10.0.1.0/24
acl manager proto cache_object
acl localhost src 127.0.0.1/32
acl SSL_ports port 443 4243 563
acl Safe_ports port 80 21 443 563 70 210 1025-65535
acl Safe_ports port 280 # http-mgmt
acl Safe_ports port 488 # gss-http
acl Safe_ports port 591 # filemaker
acl Safe_ports port 777 # multiling http
acl CONNECT method CONNECT
http_access allow manager localhost
http_access deny manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow localhost

#Estas 'refresh_pattern' fazem com que o squid mantenha o maximo
#possivel um objeto em cache, aumentando o cache HIT e byte HIT

refresh_pattern -i \.jpg$ 0 50% 21600 reload-into-ims
refresh_pattern -i \.gif$ 0 50% 21600 reload-into-ims
refresh_pattern -i \.png$ 0 50% 21600 reload-into-ims
refresh_pattern -i \.jpeg$ 0 50% 21600 reload-into-ims
refresh_pattern -i \.bmp$ 0 50% 21600 reload-into-ims
refresh_pattern -i \.tif$ 0 50% 21600 reload-into-ims
refresh_pattern -i \.tiff$ 0 50% 21600 reload-into-ims
refresh_pattern -i \.swf$ 0 50% 21600 reload-into-ims
refresh_pattern -i \.exe$ 0 50% 21600 reload-into-ims
refresh_pattern -i \.php$ 0 20% 1440 reload-into-ims
refresh_pattern -i \.html$ 0 20% 1440 reload-into-ims
refresh_pattern -i \.htm$ 0 20% 1440 reload-into-ims
refresh_pattern -i \.shtml$ 0 20% 1440 reload-into-ims
refresh_pattern -i \.shtm$ 0 20% 1440 reload-into-ims
refresh_pattern ^ftp: 1440 20% 10080
refresh_pattern ^gopher: 1440 0% 1440
refresh_pattern . 0 20% 4320

#SITES QUE NÃO ENTRAM NO CACHE###################
acl NO_CACHE url_regex -i '/etc/squid/no_cache_url'
no_cache deny NO_CACHE
#################################################
#AUTENTICAÇÕES POR USUARIO#######################

#Monica
acl u_monica proxy_auth monica
#Dayane
acl u_dayd proxy_auth dayd
#Junior
acl u_junior proxy_auth junior
#Sandra
acl u_sandra proxy_auth sandra
#Wellington
acl u_wellington proxy_auth wellington

acl u_dayd proxy_auth dayd

#Angelina
acl u_angelina proxy_auth angelina

e etc.. para todos usuarios

#USER:ROGERIO
acl u_rmartins_url_allow url_regex -i "/etc/squid/u_rogerio_allow"
http_access allow u_rmartins u_neide_url_allow
acl u_rmartins_url_deny url_regex -i "/etc/squid/u_rogerio_deny"
http_access deny u_rmartins u_rmartins_url_deny
#####################################################################
#USER:NEOMAR
acl u_neomar_url_allow url_regex -i "/etc/squid/u_neomar_allow"
http_access allow u_neomar u_neomar_url_allow
acl u_neomar_url_deny url_regex -i "/etc/squid/u_neomar_deny"
http_access deny u_neomar u_neomar_url_deny
#####################################################################
#USER:Vicente
acl u_vicente_url_allow url_regex -i "/etc/squid/u_vicente_allow"
http_access allow u_vicente u_vicente_url_allow
acl u_vicente_url_deny url_regex -i "/etc/squid/u_vicente_deny"
http_access deny u_vicente u_vicente_url_deny
##################################################################

e etc... para todos usuarios
#####################################################################

##################################################################

####################################################################
#LIBERAR AUTENTICACAO################################################
acl autenticados proxy_auth REQUIRED
http_access allow autenticados
#####################################################################
miss_access allow all
cache_mgr root
memory_pools on
#####################################################################
#BLOQUEIA TUDO#######################################################
http_access deny all
####################################################################