Chapter 6 Configuring NAT (ASA 8.2 and Earlier)

Using NAT Exemption

Step 3 In the Original area, from the Interface drop-down list, choose the interface that is connected to the hosts with real addresses that you want to exempt.

Step 4 Enter the real addresses in the Source field, or click the ... button to choose an IP address that you already defined in ASDM.

Specify the address and subnet mask using prefix/length notation, such as 10.1.1.0/24. If you enter an IP address without a mask, it is considered to be a host address, even if it ends with a 0.

Note You can later specify addresses that you do not want to exempt. For example, you can specify a subnet to exempt such as 10.1.1.0/24, but if you want to translate 10.1.1.50, then you can create a separate rule for that address that removes the exemption.

Separate multiple real addresses by a comma.

Step 5 Enter the destination addresses in the Destination field, or click the ... button to choose an IP address that you already defined in ASDM.

Specify the address and subnet mask using prefix/length notation, such as 10.1.1.0/24. If you enter an IP address without a mask, it is considered to be a host address, even if it ends with a 0.

Separate multiple destination addresses by a comma.

By default, the field shows any, which allows any destination address.

Step 6 In the NAT Exempt Direction area, choose whether you want to exempt traffic going to lower security interfaces (the default) or to higher security interfaces by clicking the appropriate radio button.

Step 7 (Optional) Enter a description in the Description field.

Step 8 Click OK.

Step 9 (Optional) If you do not want to exempt some addresses that were included in your NAT exempt rule, then create another rule to remove the exemption. Right-click the existing NAT Exempt rule, and choose Insert.

The Add NAT Exempt Rule dialog box appears.

a.Click Action: Do not exempt.

b.Complete Steps 3 through 8 to complete the rule.

The No Exempt rule is added before the Exempt rule. The order of Exempt and No Exempt rules is important. When the ASA decides whether to exempt a packet, the ASA tests the packet against each NAT exempt and No Exempt rule in the order in which the rules are listed. After a match is found, no more rules are checked.

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Cisco Systems ASA 5505, ASA 5545-X, ASA 5555-X, ASA 5585-X, ASA 5580, ASA Services Module manual Click Action Do not exempt
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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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