The 501 by itself won't filtered based upon URL, but it can ask a Websense or other system about the URLs, and allow/deny web traffic that way. Check the 'show version' of your PIX and see if you have the "URL-filtering" enabled or not. See http://www.websense.com/SupportPortal/Tutorials/1472.aspx for how to configure both ends (assuming Websense)
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...