Cisco Systems Filtering URLs and FTP Requests with an External Server

29-6
Cisco ASA Series Firewall CLI Configuration Guide
Chapter29 Configuring Filtering Services
Filtering URLs and FTP Requests with an External Server
The following example removes the configuration for downloading Java applets to a host on a protected
network:
ciscoasa(config)# no filter java http 192.168.3.3 255.255.255.255 0 0
This command allows host 192.168.3.3 to download Java applets.
Feature History for Java Applet Filtering
Table29-1 lists the release history for Java applet filtering. ASDM is backwards-compatible with
multiple platform releases, so the specific ASDM release in which support was added is not listed.
Filtering URLs and FTP Requests with an External Server
This section describes how to filter URLs and FTP requests with an external server and includes the
following topics:
•Information About URL Filtering, page29-6
•Licensing Requirements for URL Filtering, page29-7
•Guidelines and Limitations for URL Filtering, page29-7
•Identifying the Filtering Server, page29-8
•Configuring Additional URL Filtering Settings, page29-10
•Feature History for URL Filtering, page29-17
Information About URL Filtering
You can apply filtering to connection requests originating from a more secure network to a less secure
network. Although you can use ACLs to prevent outbound access to specific content servers, managing
usage this way is difficult because of the size and dynamic nature of the Internet. You can simplify
configuration and improve ASA performance by using a separate server running one of the following
Internet filtering products:
•Websense Enterprise for filtering HTTP, HTTPS, and FTP.
•McAfee SmartFilter (formerly N2H2) for filtering HTTP, HTTPS, FTP, and long URL filtering.
In long URLs, the URL in the Referer field might contain a “host:” text string, which could cause
the HTTP GET header to be incorrectly parsed as containing the HTTP Host parameter. The ASA,
however, correctly parses the Referer field even when it contains a “host:” text string and forwards
the header to the McAfee SmartFilter server with the correct Referer URL.
Table29-3 Feature History for Java Applet Filtering
Feature Name
Platform
Releases Feature Information
Java applet filtering 7.0(1) Filters specific undesirable objects from HTTP traffic, such as Java
applets, which may pose a security threat in certain situations.