Hello all, first of all I want to say thanks before for your help.

I have installed squid and dansguardian on my server, I also setup my iptables to forward port 80 communication to port 3128 (squid).
I also have remove the comment on /etc/dansguardian/dansguardianf1.conf (line "bannedextensionlist") hoping that my server would block download.

But it isn't, it still download file no matter I add in /etc/dansguardian/lists/bannedextensionlist.

Oh yeah, I also add this line to my /etc/squid/squid.conf
so that squid will consider dansguardian as it's parent.

Thanks for your help ^^.

Try reversing them, filter through dansguardian first
in your /etc/dansguardian/dansguardian.conf file set proxyport = 3128
tell dansguardian to listen to port 8080: filterport = 8080 and forward port 80 on your router to 8080

Thanks for you reply cpuobsessed, I really appreciate that ^^.
Actually, I've already done that, and it work and block the file listed on /etc/dansguardian/lists/bannedextensionlist.
But I got into another problem, my acl on squid isn't working using that way.
I have separated some IP's, some who can browse the web, and some who cannot. When I set Dansguardian first, they all can browse.
That is the reason why I put squid first.

Well, anyway, thanks for the help ^^.