squid+iptables的问题？

泪海

客户端有几十台机器，不知道为什么有很多网页都是打到一半就打不开了。
还有有些机器能直接上qq，有些机器只能设置了代理才好上qq！
以下是我squid.conf里边的内容，还请大家指点一，二！


http_port 3128
cache_mem 128 MB
cache_swap_low 90
cache_swap_high 95
maximum_object_size 1024 KB
cache_dir ufs /tmp/squid/cache 60000 16 256
cache_access_log /var/log/squid/access.log
cache_log /dev/null
cache_store_log none
debug_options ALL,1
visible_hostname proxy

acl snmppublic snmp_community public
snmp_port 3401
#snmp_access allow snmppublic all

#icp_access allow all
icp_port 0
cache_effective_user squid
cache_effective_group squid
cache_swap_high 100%
cache_swap_low 80%
half_closed_clients off
maximum_object_size 1024 KB

hierarchy_stoplist cgi-bin ?
hierarchy_stoplist -i ^https:\\ ?
acl QUERY urlpath_regex -i cgi-bin \? \.asp \.php \.jsp \.cgi
acl denyssl urlpath_regex -i ^https:\\
no_cache deny QUERY
no_cache deny denyssl

httpd_accel_host virtual
httpd_accel_port 80
httpd_accel_with_proxy on
httpd_accel_uses_host_header on
acl all src 0.0.0.0/0
acl our_networks src 172.16.0.0/16
http_access allow our_networks
http_access deny all

#acl QUERY urlpath_regex -i cgi-bin \? \.exe$ \.zip$ \.mp3$ \.mp2$ \.rm$ \.avi$
acl QUERY urlpath_regex -i \.torrent$
no_cache deny QUERY
quick_abort_min 16 KB
quick_abort_max 16 KB
quick_abort_pct 95
connect_timeout 60 seconds
read_timeout 3 minutes
request_timeout 30 seconds
client_lifetime 30 seconds
half_closed_clients off
pconn_timeout 60 seconds
#ident_timeout 10 seconds
shutdown_lifetime 10 seconds
memory_pools off
memory_pools_limit 0

reload_into_ims on