Cisco 5505 - ASA Firewall Edition Bundle, Руководство по настройке CLI

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Cisco ASA Series CLI Configuration Guide
Chapter 1 Introduction to the Cisco ASA
Firewall Functional Overview
Protecting from IP Fragments
The ASA provides IP fragment protection. This feature performs full reassembly of all ICMP error
messages and virtual reassembly of the remaining IP fragments that are routed through the ASA.
Fragments that fail the security check are dropped and logged. Virtual reassembly cannot be disabled.
Using AAA for Through Traffic
You can require authentication and/or authorization for certain types of traffic, for example, for HTTP.
The ASA also sends accounting information to a RADIUS or server.
Applying HTTP, HTTPS, or FTP Filtering
Although you can use access lists to prevent outbound access to specific websites or FTP servers,
configuring and managing web usage this way is not practical because of the size and dynamic nature of
the Internet. We recommend that you use the ASA in conjunction with a separate server running one of
the following Internet filtering products:
•
Websense Enterprise
•
Secure Computing SmartFilter
Applying Application Inspection
Inspection engines are required for services that embed IP addressing information in the user data packet
or that open secondary channels on dynamically assigned ports. These protocols require the ASA to do
a deep packet inspection.
Sending Traffic to the IPS Module
If your model supports the IPS module for intrusion prevention, then you can send traffic to the module
for inspection. The IPS module monitors and performs real-time analysis of network traffic by looking
for anomalies and misuse based on an extensive, embedded signature library. When the system detects
unauthorized activity, it can terminate the specific connection, permanently block the attacking host, log
the incident, and send an alert to the device manager. Other legitimate connections continue to operate
independently without interruption. For more information, see the documentation for your IPS module.
Sending Traffic to the Content Security and Control Module
If your model supports it, the CSC SSM provides protection against viruses, spyware, spam, and other
unwanted traffic. It accomplishes this by scanning the FTP, HTTP, POP3, and SMTP traffic that you
configure the ASA to send to it.
Applying QoS Policies
Some network traffic, such as voice and streaming video, cannot tolerate long latency times. QoS is a
network feature that lets you give priority to these types of traffic. QoS refers to the capability of a
network to provide better service to selected network traffic.