NAT Control and Same Security Traffic | Cisco Systems ASA 5545-X

Chapter 6 Configuring NAT (ASA 8.2 and Earlier)

NAT Overview

Interfaces at the same security level are not required to use NAT to communicate. However, if you configure dynamic NAT or PAT on a same security interface, then all traffic from the interface to a same security interface or an outside interface must match a NAT rule, as shown in Figure 6-4.

Figure 6-4 NAT Control and Same Security Traffic

Security

Appliance

10.1.1.1 No NAT	10.1.1.1
Level 50	Level 50

	Security
	Appliance
10.1.1.1	Dyn. NAT		209.165.201.1
10.1.2.1	No NAT
	Level 50	Level 50	132215
		or	132215
		or
		Outside

Similarly, if you enable outside dynamic NAT or PAT, then all outside traffic must match a NAT rule when it accesses an inside interface (see Figure 6-5).

Figure 6-5	NAT Control and Inbound Traffic
	Security		Security
	Appliance		Appliance
		209.165.202.129	Dyn. NAT		10.1.1.50
209.165.202.129	No NAT	209.165.202.129	No NAT
		209.165.200.240	No NAT
		209.165.200.240
	Outside	Inside	Outside	Inside	132213
	Outside	Inside	Outside	Inside

Static NAT does not cause these restrictions.

By default, NAT control is disabled; therefore, you do not need to perform NAT on any networks unless you want to do so. If you upgraded from an earlier version of software, however, NAT control might be enabled on your system. Even with NAT control disabled, you need to perform NAT on any addresses for which you configure dynamic NAT. See the “Dynamic NAT Implementation” section on page 6-17for more information about how dynamic NAT is applied.

If you want the added security of NAT control but do not want to translate inside addresses in some cases, you can apply a NAT exemption or identity NAT rule on those addresses. (See the “Using NAT Exemption” section on page 6-33for more information).

To configure NAT control, see the “Configuring NAT Control” section on page 6-16.

Note In multiple context mode, the packet classifier might rely on the NAT configuration to assign packets to contexts if you do not enable unique MAC addresses for shared interfaces. See the “How the ASA Classifies Packets” section on page 8-3in the general operations configuration guide for more information about the relationship between the classifier and NAT.

Cisco ASA Series Firewall ASDM Configuration Guide

6-5

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.

Cisco Systems ASA 5545-X, ASA 5505, ASA 5555-X, ASA 5585-X NAT Control and Same Security Traffic

Models: ASA Services Module ASA 5555-X ASA 5545-X ASA 5585-X ASA 5580 ASA 5505

Figure 6-4 NAT Control and Same Security Traffic

209.165.201.1

NAT Control and Inbound Traffic

10.1.1.50

Cisco ASA Series Firewall ASDM Configuration Guide

ASA Services Module, ASA 5555-X, ASA 5545-X, ASA 5585-X, ASA 5580 specifications