Mine

# default.
hierarchy_stoplist cgi-bin ?
acl QUERY urlpath_regex cgi-bin \?
no_cache deny QUERY
icp_port 0

# transparent proxy.
httpd_accel_host virtual
httpd_accel_port 80
httpd_accel_with_proxy on
httpd_accel_uses_host_header on

# cache, logs and mem.
cache_mem 128 MB
maximum_object_size 32768 KB
cache_dir ufs /var/squid/cache 5000 16 256
cache_access_log /var/log/squid/access.log
cache_log /var/log/squid/cache.log
cache_store_log none
cache_mgr admin@centralinf.com.br

# default acls.
acl all src 0.0.0.0/0.0.0.0
acl manager proto cache_object
acl SSL_ports port 443
acl Safe_ports port 80          # http
acl Safe_ports port 443         # https
acl Safe_ports port 1025-65535  # unregistered ports
acl CONNECT method CONNECT

# central acls.
acl bloqueados url_regex -i "/etc/squid/bloqueados"
acl central src 192.168.1.0/255.255.255.0
acl preparacao src 192.168.1.234/255.255.255.255
acl estoque src 192.168.1.141/255.255.255.255
acl cold src 192.168.1.202/255.255.255.255
acl ti src "/etc/squid/ti"

# central access.
http_access allow ti
http_access deny preparacao
http_access deny estoque
http_access deny cold
http_access deny bloqueados

# default access.
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow central
http_access deny all
http_reply_access allow all

coredump_dir /var/squid/cache