Hello Amos, thank you for your response. i actually don't know what is helper. in my mind, based on ACL function (like rep_mime_time) i'm starts to thinking about how to use external acl to matching content based on content-type, then i want to assign this acl to set tos value. i'm wondering if this could be achieve using this way. Hello Eliezer, thank you for your suggestion. i will learn more about ICAP. i'm apreciated if you could explain to me about ICAP. -- View this message in context: http://squid-web-proxy-cache.1019090.n4.nabble.com/external-acl-type-and-tos-tp4664079p4664099.html Sent from the Squid - Users mailing list archive at Nabble.com.