Default Settings and NAT Limitations, 10-4

Chapter 10 Getting Started with Application Layer Protocol Inspection

Default Settings and NAT Limitations

Inspected protocols are subject to advanced TCP-state tracking, and the TCP state of these connections is not automatically replicated. While these connections are replicated to the standby unit, there is a best-effort attempt to re-establish a TCP state.

Default Settings and NAT Limitations

By default, the configuration includes a policy that matches all default application inspection traffic and applies inspection to the traffic on all interfaces (a global policy). Default application inspection traffic includes traffic to the default ports for each protocol. You can only apply one global policy, so if you want to alter the global policy, for example, to apply inspection to non-standard ports, or to add inspections that are not enabled by default, you need to either edit the default policy or disable it and apply a new one.

Table 10-1lists all inspections supported, the default ports used in the default class map, and the inspection engines that are on by default, shown in bold. This table also notes any NAT limitations.

Table 10-1	Supported Application Inspection Engines

Application1		Default Port	NAT Limitations	Standards2	Comments
CTIQBE		TCP/2748	No extended PAT.	—	—
			No NAT64.
			(Clustering) No static PAT.

DCERPC		TCP/135	No NAT64.	—	—

DNS over UDP		UDP/53	No NAT support is available for	RFC 1123	—
			name resolution through
			WINS.

FTP		TCP/21	(Clustering) No static PAT.	RFC 959	—

GTP		UDP/3386	No extended PAT.	—	Requires a special license.
		UDP/2123	No NAT64.
			No NAT64.

H.323 H.225 and		TCP/1720	No dynamic NAT or PAT.	ITU-T H.323,	—
RAS		UDP/1718	Static PAT may not work.	H.245, H225.0,
		UDP (RAS)	Static PAT may not work.	Q.931, Q.932
		1718-1719	(Clustering) No static PAT.
			No extended PAT.
			No per-session PAT.
			No NAT on same security
			interfaces.
			No outside NAT.
			No NAT64.

HTTP		TCP/80	—	RFC 2616	Beware of MTU limitations stripping
					ActiveX and Java. If the MTU is too
					small to allow the Java or ActiveX tag to
					be included in one packet, stripping
					may not occur.

ICMP		—	—	—	—

Cisco ASA Series Firewall ASDM Configuration Guide

10-4

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 5505, ASA 5545-X, ASA 5580 Default Settings and NAT Limitations, 323 H.225, 10-4

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

Default Settings and NAT Limitations

DCERPC

FTP

H.323 H.225 and

RAS

UDP (RAS)

Cisco ASA Series Firewall ASDM Configuration Guide

10-4

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