squid认证,启动出错

markceo

FC4下squid-2.5.STABLE9-7

错误提示:
2005/10/23 14:43:00| Invalid Proxy Auth ACL 'acl auth_user proxy_auth REQUIRED' because no authentication schemes are fully configured.
FATAL: Bungled squid.conf line 1817: acl auth_user proxy_auth REQUIRED
Squid Cache (Version 2.5.STABLE9): Terminated abnormally.

squid.conf如下:
acl auth_user proxy_auth REQUIRED
authenticate_program /usr/bin/ncsa_auth /etc/squid/etc/passwd
http_access allow auth_user
http_access allow localhost
http_access deny all

如果不使用认证功能的话,可以启动,有个警告如下:
2005/10/23 14:50:18| WARNING: Very large maximum_object_size_in_memory settings can have negative impact on performance

这个警告是什么意思? 我设置认证功能错在那里??这个软件是安装系统的时候自动装上的,有影响吗?