Chapter 26 Configuring the Botnet Traffic Filter

Configuring the Botnet Traffic Filter

•You must first configure DNS inspection for traffic that you want to snoop using the Botnet Traffic Filter. See the “DNS Inspection” section on page 11-1and Chapter 1, “Configuring a Service Policy,” for detailed information about configuring advanced DNS inspection options using the Modular Policy Framework.

Note You can also configure DNS snooping directly in the Configuration > Firewall > Service Policy Rules > Rule Actions > Protocol Inspection > Select DNS Inspect Map dialog box by checking the Enable Botnet traffic filter DNS snooping check box.

Restrictions

TCP DNS traffic is not supported.

Default DNS Inspection Configuration and Recommended Configuration

The default configuration for DNS inspection inspects all UDP DNS traffic on all interfaces, and does not have DNS snooping enabled.

We suggest that you enable DNS snooping only on interfaces where external DNS requests are going. Enabling DNS snooping on all UDP DNS traffic, including that going to an internal DNS server, creates unnecessary load on the ASA.

For example, if the DNS server is on the outside interface, you should enable DNS inspection with snooping for all UDP DNS traffic on the outside interface.

Detailed Steps

Step 1 Choose the Configuration > Firewall > Botnet Traffic Filter > DNS Snooping pane.

All existing service rules that include DNS inspection are listed in the table.

Step 2 For each rule for which you want to enable DNS snooping, in the DNS Snooping Enabled column, check the check box.

Step 3 Click Apply.

What to Do Next

See the “Enabling Traffic Classification and Actions for the Botnet Traffic Filter” section on page 26-10.

Enabling Traffic Classification and Actions for the Botnet Traffic Filter

This procedure enables the Botnet Traffic Filter. The Botnet Traffic Filter compares the source and destination IP address in each initial connection packet to the following:

•Dynamic database IP addresses

•Static database IP addresses

•DNS reverse lookup cache (for dynamic database domain names)

•DNS host cache (for static database domain names)

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Cisco Systems ASA 5505, ASA 5545-X, ASA 5555-X, ASA 5585-X, ASA 5580, ASA Services Module manual 26-10
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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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