Hi, I take time to test the cache behavior with different versions I just get a picture and refresh Squid 3.0 STABLE 25 10.1.1.1 - - [07/Feb/2012:14:52:48 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 200 225918 TCP_MISS:DIRECT 10.1.1.1 - - [07/Feb/2012:14:52:51 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 282 TCP_REFRESH_UNMODIFIED:DIRECT 10.1.1.1 - - [07/Feb/2012:14:52:57 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 282 TCP_REFRESH_UNMODIFIED:DIRECT Squid 3.1.18 10.1.1.1 - - [07/Feb/2012:14:50:29 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 0 0 TCP_MISS:DIRECT 10.1.1.1 - - [07/Feb/2012:14:50:47 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 200 225909 TCP_MISS:DIRECT 10.1.1.1 - - [07/Feb/2012:14:51:04 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 275 TCP_MISS:DIRECT 10.1.1.1 - - [07/Feb/2012:14:51:16 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 275 TCP_MISS:DIRECT Squid 3.2.0.15 10.1.1.1 - - [07/Feb/2012:14:49:40 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 277 TCP_MISS:HIER_DIRECT 10.1.1.1 - - [07/Feb/2012:14:49:47 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 277 TCP_MISS:HIER_DIRECT 10.1.1.1 - - [07/Feb/2012:14:49:59 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 277 TCP_MISS:HIER_DIRECT 10.1.1.1 - - [07/Feb/2012:14:50:00 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 277 TCP_MISS:HIER_DIRECT Squid 3.1.12.1-20110523 10.1.1.1 - - [07/Feb/2012:15:04:35 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 286 TCP_MISS:DIRECT 10.1.1.1 - - [07/Feb/2012:15:04:39 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 304 286 TCP_MISS:DIRECT 10.1.1.1 - - [07/Feb/2012:15:04:44 +0100] "GET http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/giant-squid2-lw.jpg HTTP/1.1" 0 0 TCP_MISS:DIRECT Identical configuration, except squid 3.2 with workers acl QUERY urlpath_regex cgi-bin ig? /ig/ -> no change without this no_cache deny QUERY cache_mem 500 MB connect_timeout 5 minutes dns_retransmit_interval 5 seconds dns_timeout 1 minutes persistent_request_timeout 2 minutes request_timeout 60 seconds maximum_object_size_in_memory 2000 KB maximum_object_size 800 MB I tried light pictures without more success 10.1.1.1 - - [07/Feb/2012:15:08:05 +0100] "GET http://images.nationalgeographic.com/wpf/media-live/photos/000/183/cache/transparent-squid-newbert_18395_600x450.jpg HTTP/1.1" 304 347 TCP_MISS:HIER_DIRECT 10.1.1.1 - - [07/Feb/2012:15:08:13 +0100] "GET http://images.nationalgeographic.com/wpf/media-live/photos/000/183/cache/transparent-squid-newbert_18395_600x450.jpg HTTP/1.1" 304 347 TCP_MISS:HIER_DIRECT 10.1.1.1 - - [07/Feb/2012:15:08:14 +0100] "GET http://images.nationalgeographic.com/wpf/media-live/photos/000/183/cache/transparent-squid-newbert_18395_600x450.jpg HTTP/1.1" 304 347 TCP_MISS:HIER_DIRECT 10.1.1.1 - - [07/Feb/2012:15:08:15 +0100] "GET http://images.nationalgeographic.com/wpf/media-live/photos/000/183/cache/transparent-squid-newbert_18395_600x450.jpg HTTP/1.1" 304 347 TCP_MISS:HIER_DIRECT The next day, I clear my web browser's cache and retry, there is TCP_HIT:NONE with only 3.0 (although there are many HIT in access.log in 3.1 and 3.2). If this is not a bug then how to explain such behavior ? Someone can try with recent version and tell the result ? Thanks