hello sir,
with regarding to the firewall ASA5520, i'm using it in my network, all the confiuration are properly configured and working but with the use of proxy address in internet explorer(e.:206.53.155.129/3128) all the blocked contents as easily accessible simply it bypass all the network through firewall.so will u guide me to block the proxy servers.if u want the confiiguration than let me know,but as soon as possible provide me the solution for it.