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User Guide for Cisco Security Manager 4.4
OL-28826-01
Chapter 18 Managing Firewall Web Filter Rules
Configuring Settings for Web Filter Servers
Maximum Requests The maximum number of outstanding requests that can exist at any
given time. If the specified number is exceeded, new requests are
dropped. The default is 1000.
Packet Buffer The maximum number of HTTP responses that can be stored in the
packet buffer of the device while it waits for the web filter server to
allow or deny the request. The device drops responses when the
maximum is reached. The default (and maximum) value is 200.
When users make web requests, the device simultaneously sends the
request to the web site and to the web filtering server. If the response
from the web site is received before the server provides a permit or deny
response, the device keeps the request in the packet buffer until it gets
a response from the server.
The response is removed from the buffer when the server responds or if
the device determines that the server is unavailable and you also
selected Allow Traffic when Servers Unreachable.
PIX/ASA/FWSM Specific Settings
Cache Match Criteria How to cache web requests:
• Source and Destination—Cache entries are based on both the
address initiating the request and the destination web address.
Select this mode if users do not share the same filtering policy on
the filtering server.
• Destination—Cache entries are based on the destination web
address. Select this mode if all users share the same filtering policy
on the filtering server.
URL Buffer Memory
(ASA 7.2+, PIX 7.2+ only.)
The size of the URL buffer memory pool in KB. Values are 2 to 10240.
Maximum Allowed URL
Size
(ASA 7.2+, PIX 7.2+ only.)
The maximum allowed URL size in KB for each URL being buffered.
The possible values differ depending on server type:
• Websense—From 2 to 4.
• Smartfilter (N2H2)—2 or 3.
Cache Size The size of the cache, in KB, for storing responses from the filtering
server. Values are 1 to 128.
Caching stores URL access privileges in memory on the security
appliance. When a host requests a connection, the security appliance
first looks in the URL cache for matching access privileges instead of
forwarding the request to the Websense server.
URL Block Buffer Limit The size of the buffer for storing web server responses while waiting
for a filtering decision from the filtering server. The values are 1 to 128,
which specifies the number of 1550-byte blocks.
Table 18-8 Web Filter Page (Continued)
Element Description