NAT and Site-to-Site VPN, Dst | Cisco Systems ASA Services Module

Chapter 3 Information About NAT (ASA 8.3 and Later)

NAT for VPN

Figure 3-22 Identity NAT for VPN Clients

2.ASA decrypts packet; src address is now local address

		209.165.201.10			10.3.3.10

	3. Identity NAT betwee
	3. Identity NAT betwee			n inside and VPN Client NWs
					1. SMTP request to 10.1.1.6
	Src: 10.3.3.10		10.3.3.10
	Src: 10.3.3.10		10.3.3.10
	Dst: 10.1.1.6		10.1.1.6			Src: 209.165.201.10
	Dst: 10.1.1.6		10.1.1.6

4. SMTP request to 10.1.1.6

Src: 10.3.3.10
		VPN Client
		209.165.201.10
Inside	Internet	Dst: 209.165.201.10
		Dst: 209.165.201.10
10.1.1.6		8. SMTP response to
		VPN Client

	Src: 10.1.1.6	10.1.1.6

Dst: 10.3.3.10	Dst: 10.3.3.10	10.3.3.10

5. SMTP response to 6. Identity NAT VPN Client

10.3.3.10 209.165.201.10

7.ASA encrypts packet; dst address is now real address

303463

See the following sample NAT configuration for the above network:

! Enable hairpin for non-split-tunneled VPN client traffic:

same-security-traffic permit intra-interface

! Identify local VPN network, & perform object interface PAT when going to Internet:

object network vpn_local

subnet 10.3.3.0 255.255.255.0

nat (outside,outside) dynamic interface

! Identify inside network, & perform object interface PAT when going to Internet:

object network inside_nw

subnet 10.1.1.0 255.255.255.0

nat (inside,outside) dynamic interface

!Use twice NAT to pass traffic between the inside network and the VPN client without

!address translation (identity NAT):

nat (inside,outside) source static inside_nw inside_nw destination static vpn_local vpn_local

NAT and Site-to-Site VPN

Figure 3-23shows a site-to-site tunnel connecting the Boulder and San Jose offices. For traffic that you want to go to the Internet (for example from 10.1.1.6 in Boulder to www.example.com), you need a public IP address provided by NAT to access the Internet. The below example uses interface PAT rules. However, for traffic that you want to go over the VPN tunnel (for example from 10.1.1.6 in Boulder to

10.2.2.78in San Jose), you do not want to perform NAT; you need to exempt that traffic by creating an identity NAT rule. Identity NAT simply translates an address to the same address.

Cisco ASA Series Firewall ASDM Configuration Guide

3-27

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 Services Module, ASA 5505, ASA 5545-X, ASA 5555-X NAT and Site-to-Site VPN, Dst

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

Figure 3-22 Identity NAT for VPN Clients

Dst: 10.3.3.10

NAT and Site-to-Site VPN

Cisco ASA Series Firewall ASDM Configuration Guide

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