i am using squid for proxy and iptables for nating


now every thing is fine ok

i restricted the down load on time basis for .mp3 .avi . mpeg ...... mean on multimedia files
as
acl all src 192.168.0.0/255.255.255.0
acl time_acl time 11:30-23:30
acl file_proto url_regex ftp .mp3 .mov .vob .mpeg .avi
http_access deny all time_acl file_proto

now it is working but when ever i open the site
www.altavista.com
the squid restricted page is displayed
why

i found that the above site has
altAVIsta.com mean contains the word avi that's why the error squid page is display

what can i do know , i dont want to restrict this site
similarly i found many sites that contains that like words

so how can i get rid of these things

While I'm not familiar with squid, in a regular expression the period (".") is a wildcard; it matches any character. So ".avi" matches "tavi" in altavista. To prevent that, you usually escape the character with a backslash: \.avi

Also, your regex won't match upper or mixed case. So for example, "test.Avi" and "test.AVI" won't match. A quick google shows that url_regex has a "-i" option, to ignore case. So I would use:

acl file_proto url_regex -i ftp \.mp3 \.mov \.vob \.mpeg \.avi

This may still be problematic, because strings like "test.avisionary" or "anftpexample.txt" will match. Think carefully about the situation before establishing a filter.