[squid-users] expires time problem between apache and squid

[千千阙歌]

squid-users，您好！

Redhat Linux AS 4: squid2.6.STABLE16 + apache 2.0.61

1.I use apache to control cache time ,
  <IfModule mod_expires.c>
    ExpiresActive on
    ExpiresByType text/html A60
    ExpiresByType text/css A1296000
    ExpiresByType image/gif A1296000
    ExpiresByType image/jpeg A1296000
    EXpiresByType application/x-shockwave-flash A1296000
    EXpiresByType application/x-javascript      A1296000
    ExpiresDefault      A60
  </IfModule>
  
  then i found the squid can't cache , and the i change A60 to A61 , the squid 
work well!
  
2.If i use squid control the cache time，it also dosn't work!
  refresh_pattern -i ^http://media.mydomain.com/ 1 100% 1 override-lastmod 
override-expire reload-into-ims      (1 minute can't cache)
  
refresh_pattern -i ^http://media.hexun.com/ 2 100% 2 override-lastmod 
override-expire reload-into-ims      (when i set 2 minute , it works! )

  i really don't known why!
By the say: in my intranet , all server ntpdate from ntpserver every several 
minutes!