Chapter 29 Configuring Filtering Services

Filtering URLs and FTP Requests with an External Server

•Buffering the Content Server Response, page 29-5

•Caching Server Addresses, page 29-5

•Filtering HTTP URLs, page 29-6

Buffering the Content Server Response

When you issue a request to connect to a content server, the ASA sends the request to the content server and to the filtering server at the same time. If the filtering server does not respond before the content server, the server response is dropped. This behavior delays the web server response for the web client, because the web client must reissue the request.

By enabling the HTTP response buffer, replies from web content servers are buffered, and the responses are forwarded to the requesting client if the filtering server allows the connection. This behavior prevents the delay that might otherwise occur.

To configure buffering for responses to HTTP or FTP requests, perform the following steps:

Step 1 In the URL Filtering Servers pane, click Advanced to display the Advanced URL Filtering dialog box.

Step 2 In the URL Buffer Size area, check the Enable buffering check box.

Step 3 Enter the number of 1550-byte buffers. Valid values range from 1 to 128.

Step 4 Click OK to close this dialog box.

Caching Server Addresses

After you access a website, the filtering server can allow the ASA to cache the server address for a certain period of time, as long as each website hosted at the address is in a category that is permitted at all times. When you access the server again, or if another user accesses the server, the ASA does not need to consult the filtering server again.

Note Requests for cached IP addresses are not passed to the filtering server and are not logged. As a result, this activity does not appear in any reports. You can accumulate Websense run logs before using the url-cachecommand.

To improve throughput, perform the following steps:

Step 1 In the URL Filtering Servers pane, click Advanced to display the Advanced URL Filtering dialog box.

Step 2 In the URL Cache Size area, check the Enable caching based on check box to enable caching according to the specified criteria.

Step 3 Click one of the following radio buttons:

•Destination Address—This option caches entries according to the URL destination address. Choose this setting if all users share the same URL filtering policy on the Websense server.

•Source/Destination Address—This option caches entries according to both the source address that initiates the URL request and the URL destination address. Choose this setting if users do not share the same URL filtering policy on the server.

Step 4 Enter the cache size within the range from 1 to 128 (KB).

Cisco ASA Series Firewall ASDM Configuration Guide

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Cisco Systems ASA Services Module, ASA 5505, ASA 5580 Buffering the Content Server Response, Caching Server Addresses, 29-5
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ASA Services Module, ASA 5555-X, ASA 5545-X, ASA 5585-X, ASA 5580 specifications

Cisco Systems has long been a leader in the field of network security, and its Adaptive Security Appliance (ASA) series is a testament to this expertise. Within the ASA lineup, models such as the ASA 5505, ASA 5580, ASA 5585-X, ASA 5545-X, and ASA 5555-X stand out for their unique features, capabilities, and technological advancements.

The Cisco ASA 5505 is designed for small businesses or branch offices. It provides essential security features such as firewall protection, flexible VPN capabilities, and intrusion prevention. The ASA 5505 supports a user-friendly interface, allowing for straightforward management. Its built-in threat detection and prevention tools provide a layered defense, and with scalability in mind, it can accommodate various expansion options as organizational needs grow.

Moving up the line, the ASA 5580 delivers greater throughput and advanced security features. This model is suited for medium to large enterprises that require robust protection against increasingly sophisticated threats. Its multi-core architecture allows it to manage high volumes of traffic seamlessly while maintaining excellent performance levels. The ASA 5580 also supports application-layer security and customizable access policies, making it highly adaptable to diverse security environments.

The ASA 5585-X further enhances Cisco's security offerings with advanced malware protection and extensive security intelligence capabilities. It incorporates next-generation firewall features, including context-aware security, and supports advanced threat detection technologies. This model is ideal for large enterprises or data centers that prioritize security while ensuring uninterrupted network performance and availability.

For enterprises requiring a balance of performance and security, the ASA 5545-X presents a compelling option. This model features scalable performance metrics, high availability, and integrated advanced threat protection. Coupled with advanced endpoint protection and detailed monitoring capabilities, the ASA 5545-X enables organizations to manage their security posture effectively.

Lastly, the ASA 5555-X blends cutting-edge technologies with strong security infrastructures. It boasts high throughput and the ability to execute deep packet inspections. Its sophisticated architecture supports threat intelligence feeds that provide real-time security updates, making it a powerful tool against modern threats.

Each of these Cisco ASA models brings specific advantages to varied environments. Their integrative capabilities enable businesses to enhance their security postures while benefiting from seamless scalability and management. As cybersecurity threats evolve, these advanced appliances play a vital role in protecting valuable digital assets.
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