Este fichero de configuración me gusta un poco más.
#Fichero Configuracion Squid
#Localizacion: /etc/squid/squid.conf
#Liberado bajo GPL v2 o variantes
###############################
#
# Parametros generales
#
###############################
visible_hostname proxy.miproxy.local
http_port 3128 transparent
half_closed_clients off
ftp_user anonymous@nospam.com
#
#
################################
#
# CONFIGURACION CACHE
#
###############################
cache_mem 256 MB
cache_dir ufs /tmp 1024 32 256
cache_mgr user@mydomain.com
coredump_dir /var/spool/squid/cache
acl manager proto cache_object
cache_access_log /var/log/squid/access.log
error_directory /usr/share/squid/errors/Spanish/
###################################
#
# CONTROL ANCHO DE BANDA(DELAY POOLS)
#
###################################
delay_pools 3
delay_class 1 1
delay_class 2 1
delay_class 3 1
delay_parameters 1 51200/358400
delay_parameters 2 76800/358400
delay_parameters 3 102400 /358400
delay_initial_bucket_level 90
##############################
#
# TIEMPOS DE REFRESCO X FICHERO
#
##############################
#
#Refresco de la cache MIN PORCENTAJE MAX(MIN)
#
#1440 = 1 dia
#2880 = 2 dias
#10080 = 7 dias
#20160 = 14 dias
#30240 = 21 dias
#
#Ficheros comunes en sistemas
refresh_pattern \.iso$ 2880 80% 30240
refresh_pattern \.deb$ 2880 80% 30240
refresh_pattern \.tar.gz$ 2880 80% 30240
refresh_pattern \.gz$ 2880 80% 30240
refresh_pattern \.bz2$ 2880 80% 30240
refresh_pattern \.exe$ 2880 80% 30240
#
#
#Ficheros de imagenes
refresh_pattern \.jpg$ 1440 50% 2880
refresh_pattern \.jpeg$ 1440 50% 2880
refresh_pattern \.gif$ 1440 50% 2880
refresh_pattern \.bmp$ 1440 50% 2880
refresh_pattern \.png$ 1440 50% 2880
refresh_pattern \.svg$ 1440 50% 2880
refresh_pattern \.tif$ 1440 50% 2880
refresh_pattern \.tiff$ 1440 50% 2880
#
#
#Documentos
refresh_pattern \.xls$ 1440 80% 2880
refresh_pattern \.doc$ 1440 80% 2880
refresh_pattern \.odt$ 1440 80% 2880
refresh_pattern \.rtf$ 1440 80% 2880
refresh_pattern \.jpeg$ 1440 80% 2880
refresh_pattern \.pdf$ 1440 80% 2880
#
#
#Ficheros comprimidos
refresh_pattern \.zip$ 2880 80% 4320
refresh_pattern \.rar$ 2880 80% 4320
refresh_pattern \.arj$ 2880 80% 4320
#
#
####################################
#
# LISTAS DE CONTROL DE ACCESO(ACLS)
#
####################################
acl SSL_ports port 443 563
acl Safe_ports port 80
acl Safe_ports port 21
acl Safe_ports port 20
acl Safe_ports port 443 563
acl Safe_ports port 777
acl all src 0.0.0.0/0.0.0.0
acl localhost src 127.0.0.1/255.255.255.255
acl lan src 192.168.1.0/255.255.255.0
acl del1 src 192.168.2.0/255.255.255.0
acl del2 src 192.168.3.0/255.255.255.0
acl del3 src 192.168.4.0/255.255.255.0
acl del4 src 192.168.5.0/255.255.255.0
acl wifi src 172.16.0.0/255.255.255.240
acl denywords url_regex "/etc/squid/denywords"
acl denydomains dstdom_regex "/etc/squid/denydomains"
#
#
#
delay_access 2 allow lan
delay_access 2 allow del1
delay_access 2 allow del2
delay_access 2 allow del3
delay_access 2 allow del4
delay_access 2 deny all
delay_access 3 deny all
delay_access 1 deny all
#
#
http_access deny denywords
http_access deny denydomains
http_access allow lan
http_access allow wifi
http_access allow del1
http_access deny all