How to create an acl source IP which matches nothing ? acl link1 src xx What is the xx which I need to put so that it will not match anything ? I tried doing xx = ! 0/0. But squid complaints that it's not valid. Reason I want to this is that I am keeping the acl parameters in external file, I want it to matching nothing for default, and when needed, I change through the external file for it to match specific IPs or subnet. Best regards.