squid 认证问题

whn3375

linux下的squid.conf内容如下:
auth_param basic program /usr/lib/squid/ncsa_auth /etc/squid/passwd
auth_param basic children 5
auth_param basic realm Squid proxy-caching web server
auth_param basic credentialsttl 2 hours
auth_param basic casesensitive off

negative_ttl 3 seconds
positive_dns_ttl 10 minutes
peer_connect_timeout 10 seconds
request_timeout 1 minute
persistent_request_timeout 20 seconds
client_lifetime 2 minutes
half_closed_clients off
pconn_timeout 20 seconds

acl sum max_user_ip 2
authenticate_ip_ttl 120 seconds
#authenticate_ip_ttl_is_strict on
request_header_max_size 50 KBacl all src 0.0.0.0/0.0.0.0
acl CONNECT method CONNECT


acl foo proxy_auth REQUIRED
http_access deny sum
http_access allow foo
http_access deny all

1. TTL问题
实现了NCSA认证,但是一次认证后就没有再出现过认证画面
ps -ef|grep ncsa 有5个ncsa_auth进行中
less /usr/local/squid/var/logs/cache.log
helperOpenServers: Starting 5 'ncsa_auth' processes

2. authenticate_ip_ttl_is_strict on的设置需要什么额外的条件吗
  check 和reconfig时出错
  parseConfigFile: line 30 unrecognized: 'authenticate_ip_ttl_is_strict on '
  
3. linux下成功了,为什么Windows IE下不可以使用这个proxy?
  应该和max_user_ip的设定没有关系.

请指教!