Configuring IP Fragment Reassembly

Chapter 7 Defining Signatures

Configuring Signatures

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This section describes IP fragment reassembly, lists the IP fragment reassembly signatures with the configurable parameters, describes how to configure these parameters, and how to configure the method for IP fragment reassembly. It contains the following topics:

•Understanding IP Fragment Reassembly, page 7-28

•IP Fragment Reassembly Signatures and Configurable Parameters, page 7-28

•Configuring IP Fragment Reassembly Parameters, page 7-30

•Configuring the Method for IP Fragment Reassembly, page 7-30

Understanding IP Fragment Reassembly

You can configure the sensor to reassemble a datagram that has been fragmented over multiple packets. You can specify boundaries that the sensor uses to determine how many datagram fragments it reassembles and how long to wait for more fragments of a datagram. The goal is to ensure that the sensor does not allocate all its resources to datagrams that cannot be completely reassembled, either because the sensor missed some frame transmissions or because an attack has been launched that is based on generating random fragmented datagrams.

Note You configure the IP fragment reassembly per signature.

IP Fragment Reassembly Signatures and Configurable Parameters

Table 7-5lists IP fragment reassembly signatures with the parameters that you can configure for IP fragment reassembly. The IP fragment reassembly signatures are part of the Normalizer engine.

Table 7-5		IP Fragment Reassembly Signatures

				Parameter With Default Value
	Signature ID and Name		Description	and Range	Default Action

	1200 IP Fragmentation		Fires when the total number of	Specify Max Fragments 10000	Deny Packet Inline
	Buffer Full		fragments in the system exceeds the	(0-42000)	Produce Alert1
			threshold set by Max Fragments.

	1201 IP Fragment Overlap		Fires when the fragments queued for	—2	Deny Packet Inline
			a datagram overlap each other.		Produce Alert1
	1202 IP Fragment Overrun		Fires when the fragment data (offset	Specify Max Datagram Size	Deny Packet Inline
	- Datagram Too Long		and size) exceeds the threshold set	65536 (2000-65536)	Produce Alert3
			with Max Datagram Size.

	1203 IP Fragment		Fires when the fragments queued for	—	Deny Packet Inline
	Overwrite - Data is		a datagram overlap each other and		Produce Alert5
	Overwritten		the overlapping data is different.4
		Cisco Intrusion Prevention System Sensor CLI Configuration Guide for IPS 7.2

	7-28				OL-29168-01
	7-28				OL-29168-01

IPS4510K9 specifications

Cisco Systems has long been a leading player in network security, and its IPS (Intrusion Prevention System) series is a testament to its commitment to safeguarding digital environments. Among its notable offerings are the IPS4510K9 and IPS4520K9 models, both designed to provide advanced threat protection for mid-sized to large enterprise networks.

The Cisco IPS4510K9 and IPS4520K9 are distinguished by their cutting-edge features that help organizations defend against a myriad of cyber threats. These systems utilize a multi-layered approach to security, integrating intrusion prevention, advanced malware protection, and comprehensive visibility across the network.

One of the primary characteristics of the IPS4510K9 is its high performance. It boasts a throughput of up to 1 Gbps, making it suitable for environments that demand rapid data processing and real-time responses to threats. The IPS4520K9, on the other hand, enhances that capability with improved throughput of up to 2 Gbps, accommodating larger enterprises with heavier network traffic. These models are equipped with powerful processors that support complex signature matching and can intelligently distinguish between legitimate traffic and potential threats.

In addition to performance, both models are designed with scalability in mind. They can be easily integrated into existing Cisco infrastructures. This facilitates a seamless enhancement of security without causing significant interruptions to ongoing operations. Moreover, they offer flexible deployment options, allowing organizations to operate them inline or out of band depending on their specific needs.

The Cisco IPS4510K9 and IPS4520K9 leverage advanced detection technologies, utilizing a variety of signature types and heuristic analysis to detect known and unknown threats effectively. They are equipped with real-time alerting and reporting capabilities, giving security teams immediate visibility into potential breaches and enabling them to respond swiftly.

Furthermore, both models support a range of management options through the Cisco Security Manager, allowing for centralized administration, streamlined policy management, and enhanced monitoring capabilities. Automated updates ensure the systems remain current with the latest threat intelligence, vital for staying ahead of evolving cyber threats.

In summary, the Cisco Systems IPS4510K9 and IPS4520K9 represent powerful solutions for organizations seeking robust intrusion prevention capabilities. With their high performance, scalability, and advanced detection technologies, these systems are essential tools in the ever-changing landscape of cybersecurity, providing enterprises with the peace of mind needed to operate securely in today's digital world.

Cisco Systems IPS4510K9 Configuring IP Fragment Reassembly, Understanding IP Fragment Reassembly

Models: IPS4510K9

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