Hi, Please need your guidance regarding the regex used by squid. Is it bre ere or perl? I assume that squid using a gnurep compatible version? Am i right? In grep to use some metacharacter we have to encode it which are ‘\?’, ‘\+’, ‘\{’, ‘\|’, ‘\(’, and ‘\)’ does this hold true to write regex for squid as well? acl MP3url urlpath_regex \.mp3(\?.*)?$ isnt this expression should be written as \.mp3'\(''\?'.*'\)''\?'$ please guidance regarding this will be of great value to me. thanks & Regards, Bilal _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. https://signup.live.com/signup.aspx?id=60969