Attack detection and prevention enables a device to detect attacks by inspecting arriving packets, and to take prevention actions to protect a private network. Prevention actions include logging and packet dropping.

Attacks that the device can prevent

This section describes the attacks that the device can detect and prevent.

Single-packet attacks

Single-packet attacks are also known as malformed packet attacks. An attacker typically launches single-packet attacks by using the following methods:

· An attacker sends defective packets to a device, which causes the device to malfunction or crash.

· An attacker sends normal packets to a device, which interrupts connections or probes network topologies.

· An attacker sends a large number of forged packets to a target device, which consumes network bandwidth and causes denial of service (DoS).

Table 1 lists the single-packet attack types that the device can detect and prevent.

Table 1 Types of single-packet attacks

Single-packet attack	Description
ICMP redirect	An attacker sends ICMP redirect messages to modify the victim's routing table. The victim cannot forward packets correctly.
ICMP destination unreachable	An attacker sends ICMP destination unreachable messages to cut off the connections between the victim and its destinations.
ICMP type	A receiver responds to an ICMP packet according to its type. An attacker sends forged ICMP packets of a specific type to affect the packet processing of the victim.
ICMPv6 type	A receiver responds to an ICMPv6 packet according to its type. An attacker sends forged ICMPv6 packets of specific types to affect the packet processing of the victim.
Land	An attacker sends the victim a large number of TCP SYN packets, which contain the victim's IP address as the source and destination IP addresses. This attack exhausts the half-open connection resources on the victim, and locks the victim's system.
Large ICMP packet	An attacker sends large ICMP packets to crash the victim. Large ICMP packets can cause memory allocation error and crash the protocol stack.
Large ICMPv6 packet	An attacker sends large ICMPv6 packets to crash the victim. Large ICMPv6 packets can cause memory allocation error and crash the protocol stack.
IP options	An attacker sends IP datagrams in which the IP options are abnormal. This attack intends to probe the network topology. The target system will break down if it is incapable of processing error packets.
IP fragment	An attacker sends the victim an IP datagram with an offset smaller than 5, which causes the victim to malfunction or crash.
IP impossible packet	An attacker sends IP packets whose source IP address is the same as the destination IP address, which causes the victim to malfunction.
Tiny fragment	An attacker makes the fragment size small enough to force Layer 4 header fields into the second fragment. These fragments can pass the packet filtering because they do not hit any match.
Smurf	An attacker broadcasts an ICMP echo request to target networks. These requests contain the victim's IP address as the source IP address. Every receiver on the target networks will send an ICMP echo reply to the victim. The victim will be flooded with replies, and will be unable to provide services. Network congestion might occur.
TCP flag	An attacker sends packets with defective TCP flags to probe the operating system of the target host. Different operating systems process unconventional TCP flags differently. The target system will break down if it processes this type of packets incorrectly.
Traceroute	An attacker uses traceroute tools to probe the topology of the victim network.
WinNuke	An attacker sends Out-Of-Band (OOB) data to the TCP port 139 (NetBIOS) on the victim that runs Windows system. The malicious packets contain an illegal Urgent Pointer, which causes the victim's operating system to crash.
UDP bomb	An attacker sends a malformed UDP packet. The length value in the IP header is larger than the IP header length plus the length value in the UDP header. When the target system processes the packet, a buffer overflow can occur, which causes a system crash.
UDP Snork	An attacker sends a UDP packet with destination port 135 (the Microsoft location service) and source port 135, 7, or 19. This attack causes an NT system to exhaust its CPU.
UDP Fraggle	An attacker sends a large number of chargen packets with source UDP port 7 and destination UDP port 19 to a network. These packets use the victim's IP address as the source IP address. Replies will flood the victim, resulting in DoS.
Teardrop	An attacker sends a stream of overlapping fragments. The victim will crash when it tries to reassemble the overlapping fragments.
Ping of death	An attacker sends the victim an ICMP echo request larger than 65535 bytes that violates the IP protocol. When the victim reassembles the packet, a buffer overflow can occur, which causes a system crash.

Scanning attacks

Scanning is a preintrusion activity used to prepare for intrusion into a network. The scanning allows the attacker to find a way into the target network and to disguise the attacker's identity.

Attackers use scanning tools to probe a network, find vulnerable hosts, and discover services that are running on the hosts. Attackers can use the information to launch attacks.

The device can detect and prevent the IP sweep and port scan attacks. If an attacker performs port scanning from multiple hosts to the target host, distributed port scan attacks occur.

Flood attacks

An attacker launches a flood attack by sending a large number of forged requests to the victim in a short period of time. The victim is too busy responding to these forged requests to provide services for legal users, and a DoS attack occurs.

The device can detect and prevent the following types of flood attacks:

· SYN flood attack.

A SYN flood attacker exploits the TCP three-way handshake characteristics and makes the victim unresponsive to legal users. An attacker sends a large number of SYN packets with forged source addresses to a server. This causes the server to open a large number of half-open connections and respond to the requests. However, the server will never receive the expected ACK packets. The server is unable to accept new incoming connection requests because all of its resources are bound to half-open connections.

· ACK flood attack.

An ACK packet is a TCP packet only with the ACK flag set. Upon receiving an ACK packet from a client, the server must search half-open connections for a match.

An ACK flood attacker sends a large number of ACK packets to the server. This causes the server to be busy searching for half-open connections, and the server is unable to process packets for normal services.

· SYN-ACK flood attack.

Upon receiving a SYN-ACK packet, the server must search for the matching SYN packet it has sent. A SYN-ACK flood attacker sends a large number of SYN-ACK packets to the server. This causes the server to be busy searching for SYN packets, and the server is unable to process packets for normal services.

· FIN flood attack.

FIN packets are used to shut down TCP connections.

A FIN flood attacker sends a large number of forged FIN packets to a server. The victim might shut down correct connections, or be unable to provide services because it is busy searching for matching connections.

· RST flood attack.

RST packets are used to abort TCP connections when TCP connection errors occur.

An RST flood attacker sends a large number of forged RST packets to a server. The victim might shut down correct connections, or be unable to provide services because it is busy searching for matching connections.

· DNS flood attack.

The DNS server processes and replies all DNS queries that it receives.

A DNS flood attacker sends a large number of forged DNS queries. This attack consumes the bandwidth and resources of the DNS server, which prevents the server from processing and replying legal DNS queries.

· HTTP flood attack.

Upon receiving an HTTP GET request, the HTTP server performs complex operations, including character string searching, database traversal, data reassembly, and format switching. These operations consume a large amount of system resources.

An HTTP flood attacker sends a large number of HTTP GET requests that exceed the processing capacity of the HTTP server, which causes the server to crash.

· ICMP flood attack.

An ICMP flood attacker sends ICMP request packets, such as ping packets, to a host at a fast rate. Because the target host is busy replying to these requests, it is unable to provide services.

· ICMPv6 flood attack.

An ICMPv6 flood attacker sends ICMPv6 request packets, such as ping packets, to a host at a fast rate. Because the target host is busy replying to these requests, it is unable to provide services.

· UDP flood attack.

A UDP flood attacker sends UDP packets to a host at a fast rate. These packets consume a large amount of the target host's bandwidth, so the host cannot provide other services.

TCP fragment attack

An attacker launches TCP fragment attacks by sending attack TCP fragments defined in RFC 1858:

· First fragments in which the TCP header is smaller than 20 bytes.

· Non-first fragments with a fragment offset of 8 bytes (FO=1).

Typically, packet filter detects the source and destination IP addresses, source and destination ports, and transport layer protocol of the first fragment of a TCP packet. If the first fragment passes the detection, all subsequent fragments of the TCP packet are allowed to pass through.

Because the first fragment of attack TCP packets does not hit any match in the packet filter, the subsequent fragments can all pass through. After the receiving host reassembles the fragments, a TCP fragment attack occurs.

To prevent TCP fragment attacks, enable TCP fragment attack prevention to drop attack TCP fragments.

Login dictionary attack

The login dictionary attack is an automated process to attempt to log in by trying all possible passwords from a pre-arranged list of values (the dictionary). Multiple login attempts can occur in a short period of time.

You can configure the login delay feature to slow down the login dictionary attacks. This feature enables the device to delay accepting another login request after detecting a failed login attempt for a user.

Compatibility information

Feature and hardware compatibility

Hardware series	Model	Attack detection and prevention compatibility
WX1800H series	WX1804H WX1810H WX1820H	Yes
WX2500H series	WX2510H WX2540H WX2560H	Yes
WX3000H series	WX3010H WX3010H-L WX3010H-X WX3024H WX3024H-L	No
WX3500H series	WX3508H WX3510H WX3520H WX3540H	Yes
WX5500E series	WX5510E WX5540E	Yes
WX5500H series	WX5540H WX5560H WX5580H	Yes
Access controller modules	EWPXM1MAC0F EWPXM1WCME0 EWPXM2WCMD0F LSQM1WCMX20 LSQM1WCMX40 LSUM1WCME0 LSUM1WCMX20RT LSUM1WCMX40RT	Yes

Command and hardware compatibility

The WX1800H series and WX2500H series access controllers do not support the slot keyword or the slot-number argument.

Attack detection and prevention configuration task list

Tasks at a glance
(Required.) Configuring an attack defense policy: · (Required.) Creating an attack defense policy · (Required.) Perform at least one of the following tasks to configure attack detection: ¡ Configuring a single-packet attack defense policy ¡ Configuring a scanning attack defense policy ¡ Configuring a flood attack defense policy · (Optional.) Configuring attack detection exemption
(Required.) Perform at least one of the tasks to apply an attack defense policy: · Applying an attack defense policy to an interface · Applying an attack defense policy to the device
(Optional.) Disabling log aggregation for single-packet attack events
(Optional.) Configuring TCP fragment attack prevention
(Optional.) Enabling the login delay

Configuring an attack defense policy

Creating an attack defense policy

An attack defense policy can contain a set of attack detection and prevention configuration against multiple attacks.

To create an attack defense policy:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Create an attack defense policy and enter its view.	attack-defense policy policy-name	By default, no attack defense policy exists.

Configuring a single-packet attack defense policy

Apply the single-packet attack defense policy to the interface that is connected to the external network.

Single-packet attack detection inspects incoming packets based on the packet signature. If an attack packet is detected, the device can take the following actions:

· Output logs (the default action).

· Drop attack packets.

You can also configure the device to not take any actions.

To configure a single-packet attack defense policy:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Configure signature detection for single-packet attacks.	· signature detect { fraggle \| fragment \| impossible \| land \| large-icmp \| large-icmpv6 \| smurf \| snork \| tcp-all-flags \| tcp-fin-only \| tcp-invalid-flags \| tcp-null-flag \| tcp-syn-fin \| tiny-fragment \| traceroute \| udp-bomb \| winnuke } [ action { { drop \| logging } * \| none } ] · signature detect { ip-option-abnormal \| ping-of-death \| teardrop } action { drop \| logging } * · signature detect icmp-type { icmp-type-value \| address-mask-reply \| address-mask-request \| destination-unreachable \| echo-reply \| echo-request \| information-reply \| information-request \| parameter-problem \| redirect \| source-quench \| time-exceeded \| timestamp-reply \| timestamp-request } [ action { { drop \| logging } * \| none } ] · signature detect icmpv6-type { icmpv6-type-value \| destination-unreachable \| echo-reply \| echo-request \| group-query \| group-reduction \| group-report \| packet-too-big \| parameter-problem \| time-exceeded } [ action { { drop \| logging } * \| none } ] · signature detect ip-option { option-code \| internet-timestamp \| loose-source-routing \| record-route \| route-alert \| security \| stream-id \| strict-source-routing } [ action { { drop \| logging } * \| none } ]	By default, signature detection is not configured for single-packet attacks. You can configure signature detection for multiple single-packet attacks.
4. (Optional.) Set the maximum length of safe ICMP or ICMPv6 packets.	signature { large-icmp \| large-icmpv6 } max-length length	By default, the maximum length of safe ICMP or ICMPv6 packets is 4000 bytes. A large ICMP or ICMPv6 attack occurs if an ICMP or ICMPv6 packet larger than the specified length is detected.
5. (Optional.) Specify the actions against single-packet attacks of a specific level.	signature level { high \| info \| low \| medium } action { { drop \| logging } * \| none }	The default action is logging for single-packet attacks of the informational and low levels. The default actions are logging and drop for single-packet attacks of the medium and high levels.
6. (Optional.) Enable signature detection for single-packet attacks of a specific level.	signature level { high \| info \| low \| medium } detect	By default, signature detection is disabled for all levels of single-packet attacks.

Configuring a scanning attack defense policy

Apply a scanning attack defense policy to the interface that is connected to the external network.

Scanning attack detection inspects the incoming packet rate of connections to the target system. If a source initiates connections at a rate equal to or exceeding the pre-defined threshold, the device can take the following actions:

· Output logs.

· Drop subsequent packets from the IP address of the attacker.

To configure a scanning attack defense policy:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Configure scanning attack detection.	scan detect level { high \| low \| medium } action { drop \| logging } *	By default, scanning attack detection is not configured.

Configuring a flood attack defense policy

Apply a flood attack defense policy to the interface that is connected to the external network to protect internal servers.

Flood attack detection monitors the rate at which connections are initiated to the internal servers.

With flood attack detection enabled, the device is in attack detection state. When the packet sending rate to an IP address reaches the threshold, the device enters prevention state and takes the specified actions. When the rate is below the silence threshold (three-fourths of the threshold), the device returns to the attack detection state.

You can configure flood attack detection and prevention for a specific IP address. For non-specific IP addresses, the device uses the global attack prevention settings.

Configuring a SYN flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global SYN flood attack detection.	syn-flood detect non-specific	By default, global SYN flood attack detection is disabled.
4. Set the global trigger threshold for SYN flood attack prevention.	syn-flood threshold threshold-value	The default setting is 1000.
5. Specify global actions against SYN flood attacks.	syn-flood action { drop \| logging } *	By default, no global action is specified for SYN flood attacks.
6. Configure IP address-specific SYN flood attack detection.	syn-flood detect { ip ip-address \| ipv6 ipv6-address } [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific SYN flood attack detection is not configured.

Configuring an ACK flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global ACK flood attack detection.	ack-flood detect non-specific	By default, global ACK flood attack detection is disabled.
4. Set the global trigger threshold for ACK flood attack prevention.	ack-flood threshold threshold-value	The default setting is 1000.
5. Specify global actions against ACK flood attacks.	ack-flood action { drop \| logging } *	By default, no global action is specified for ACK flood attacks.
6. Configure IP address-specific ACK flood attack detection.	ack-flood detect { ip ip-address \| ipv6 ipv6-address } [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific ACK flood attack detection is not configured.

Configuring a SYN-ACK flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global SYN-ACK flood attack detection.	syn-ack-flood detect non-specific	By default, global SYN-ACK flood attack detection is disabled.
4. Set the global trigger threshold for SYN-ACK flood attack prevention.	syn-ack-flood threshold threshold-value	The default setting is 1000.
5. Specify global actions against SYN-ACK flood attacks.	syn-ack-flood action { drop \| logging } *	By default, no global action is specified for SYN-ACK flood attacks.
6. Configure IP address-specific SYN-ACK flood attack detection.	syn-ack-flood detect { ip ip-address \| ipv6 ipv6-address } [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific SYN-ACK flood attack detection is not configured.

Configuring a FIN flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global FIN flood attack detection.	fin-flood detect non-specific	By default, global FIN flood attack detection is disabled.
4. Set the global trigger threshold for FIN flood attack prevention.	fin-flood threshold threshold-value	The default setting is 1000.
5. Specify global actions against FIN flood attacks.	fin-flood action { drop \| logging } *	By default, no global action is specified for FIN flood attacks.
6. Configure IP address-specific FIN flood attack detection.	fin-flood detect { ip ip-address \| ipv6 ipv6-address } [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific FIN flood attack detection is not configured.

Configuring an RST flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global RST flood attack detection.	rst-flood detect non-specific	By default, global RST flood attack detection is disabled.
4. Set the global trigger threshold for RST flood attack prevention.	rst-flood threshold threshold-value	The default setting is 1000.
5. Specify global actions against RST flood attacks.	rst-flood action { drop \| logging } *	By default, no global action is specified for RST flood attacks.
6. Configure IP address-specific RST flood attack detection.	rst-flood detect { ip ip-address \| ipv6 ipv6-address } [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific RST flood attack detection is not configured.

Configuring an ICMP flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global ICMP flood attack detection.	icmp-flood detect non-specific	By default, global ICMP flood attack detection is disabled.
4. Set the global trigger threshold for ICMP flood attack prevention.	icmp-flood threshold threshold-value	The default setting is 1000.
5. Specify global actions against ICMP flood attacks.	icmp-flood action { drop \| logging } *	By default, no global action is specified for ICMP flood attacks.
6. Configure IP address-specific ICMP flood attack detection.	icmp-flood detect ip ip-address [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific ICMP flood attack detection is not configured.

Configuring an ICMPv6 flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global ICMPv6 flood attack detection.	icmpv6-flood detect non-specific	By default, global ICMPv6 flood attack detection is disabled.
4. Set the global trigger threshold for ICMPv6 flood attack prevention.	icmpv6-flood threshold threshold-value	The default setting is 1000.
5. Specify global actions against ICMPv6 flood attacks.	icmpv6-flood action { drop \| logging } *	By default, no global action is specified for ICMPv6 flood attacks.
6. Configure IP address-specific ICMPv6 flood attack detection.	icmpv6-flood detect ipv6 ipv6-address [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific ICMPv6 flood attack detection is not configured.

Configuring a UDP flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global UDP flood attack detection.	udp-flood detect non-specific	By default, global UDP flood attack detection is disabled.
4. Set the global trigger threshold for UDP flood attack prevention.	udp-flood threshold threshold-value	The default setting is 1000.
5. Specify global actions against UDP flood attacks.	udp-flood action { drop \| logging } *	By default, no global action is specified for UDP flood attacks.
6. Configure IP address-specific UDP flood attack detection.	udp-flood detect { ip ip-address \| ipv6 ipv6-address } [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific UDP flood attack detection is not configured.

Configuring a DNS flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global DNS flood attack detection.	dns-flood detect non-specific	By default, global DNS flood attack detection is disabled.
4. Set the global trigger threshold for DNS flood attack prevention.	dns-flood threshold threshold-value	The default setting is 1000.
5. (Optional.) Specify the global ports to be protected against DNS flood attacks.	dns-flood port port-list	By default, DNS flood attack prevention protects port 53.
6. Specify global actions against DNS flood attacks.	dns-flood action { drop \| logging } *	By default, no global action is specified for DNS flood attacks.
7. Configure IP address-specific DNS flood attack detection.	dns-flood detect { ip ip-address \| ipv6 ipv6-address } [ port port-list ] [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific DNS flood attack detection is not configured.

Configuring an HTTP flood attack defense policy

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Enable global HTTP flood attack detection.	http-flood detect non-specific	By default, global HTTP flood attack detection is disabled.
4. Set the global trigger threshold for HTTP flood attack prevention.	http-flood threshold threshold-value	The default setting is 1000.
5. (Optional.) Specify the global ports to be protected against HTTP flood attacks.	http-flood port port-list	By default, HTTP flood attack prevention protects port 80.
6. Specify global actions against HTTP flood attacks.	http-flood action { drop \| logging } *	By default, no global action is specified for HTTP flood attacks.
7. Configure IP address-specific HTTP flood attack detection.	http-flood detect { ip ip-address \| ipv6 ipv6-address } [ port port-list ] [ threshold threshold-value ] [ action { { drop \| logging } * \| none } ]	By default, IP address-specific HTTP flood attack detection is not configured.

Configuring attack detection exemption

The attack defense policy uses the ACL to identify exempted packets. The policy does not check the packets permitted by the ACL. You can configure the ACL to identify packets from trusted servers. The exemption feature reduces the false alarm rate and improves packet processing efficiency.

If an ACL is used for attack detection exemption, only the following match criteria in the ACL permit rules take effect:

· Source IP address.

· Destination IP address.

· Source port.

· Destination port.

· Protocol.

· fragment keyword for matching non-first fragments.

To configure attack detection exemption:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter attack defense policy view.	attack-defense policy policy-name	N/A
3. Configure attack detection exemption.	exempt acl [ ipv6 ] { acl-number \| name acl-name }	By default, the attack defense policy applies to all incoming packets.

Applying an attack defense policy to an interface

An attack defense policy does not take effect unless you apply it to an interface.

If you apply an attack defense policy to a global interface, specify a service card to process traffic for the interface. If you do not specify a service card, the policy cannot correctly detect and prevent scanning and flood attacks.

To apply an attack defense policy to an interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter system view.	interface interface-type interface-number	N/A
3. Apply an attack defense policy to the interface.	attack-defense apply policy policy-name	By default, no attack defense policy is applied to the interface.

Applying an attack defense policy to the device

An attack defense policy applied to the device itself rather than the interfaces detects packets destined for the device and prevents attacks targeted at the device.

If a device and its interfaces have attack defense policies applied, a packet destined for the device is processed as follows:

1. The policy applied to the receiving interface processes the packet.

2. If the packet is not dropped by the receiving interface, the policy applied to the device processes the packet.

To apply an attack defense policy to the device:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Apply an attack defense policy to the device.	attack-defense local apply policy policy-name	By default, no attack defense policy is applied to the device.

Disabling log aggregation for single-packet attack events

Log aggregation aggregates all logs generated in a period and sends one log. The logs with the same attributes for the following items can be aggregated:

· Interface where the attack is detected.

· Attack type.

· Attack defense action.

· Source and destination IP addresses.

H3C recommends that you not disable log aggregation. A large number of logs will consume the display resources of the console.

To disable log aggregation for single-packet attack events:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Disable log aggregation for single-packet attack events.	attack-defense signature log non-aggregate	By default, log aggregation is enabled for single-packet attack events.

Configuring TCP fragment attack prevention

The TCP fragment attack prevention feature detects the length and fragment offset of received TCP fragments and drops attack TCP fragments.

TCP fragment attack prevention takes precedence over single-packet attack prevention. When both are used, incoming TCP packets are processed first by TCP fragment attack prevention and then by the single-packet attack defense policy.

To configure TCP fragment attack prevention:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enable TCP fragment attack prevention.	attack-defense tcp fragment enable	By default, TCP fragment attack prevention is enabled. TCP fragment attack prevention is typically used alone.

Step

Command

Remarks

1. Enter system view.

system-view

N/A

2. Enable TCP fragment attack prevention.

attack-defense tcp fragment enable

By default, TCP fragment attack prevention is enabled.

TCP fragment attack prevention is typically used alone.

Enabling the login delay

The login delay feature delays the device to accept a login request from a user after the user fails a login attempt. This feature can slow down login dictionary attacks.

To enable the login delay:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enable the login delay feature.	attack-defense login reauthentication-delay seconds	By default, the login delay feature is disabled. The device does not delay accepting a login request from a user who has failed a login attempt.

Displaying and maintaining attack detection and prevention

Use the display commands in any view and the reset commands in user view.

To display and maintain attack detection and prevention:

Task	Command
Display attack detection and prevention statistics on an interface.	display attack-defense statistics interface interface-type interface-number [ slot slot-number ]
Display attack detection and prevention statistics for the device.	display attack-defense statistics local [ slot slot-number ]
Display attack defense policy configuration.	display attack-defense policy [ policy-name ]
Display information about IPv4 scanning attackers.	display attack-defense scan attacker ip [ interface interface-type interface-number [ slot slot-number ] \| local ] [ count ]
Display information about IPv6 scanning attackers.	display attack-defense scan attacker ipv6 [ interface interface-type interface-number [ slot slot-number ] \| local ] [ count ]
Display information about IPv4 scanning attack victims.	display attack-defense scan victim ip [ interface interface-type interface-number [ slot slot-number ] \| local ] [ count ]
Display information about IPv6 scanning attack victims.	display attack-defense scan victim ipv6 [ interface interface-type interface-number [ slot slot-number ] \| local ] [ count ]
Display flood attack detection and prevention statistics for an IPv4 address.	display attack-defense { ack-flood \| dns-flood \| fin-flood \| flood \| http-flood \| icmp-flood \| rst-flood \| syn-ack-flood \| syn-flood \| udp-flood } statistics ip [ ip-address ] [ interface interface-type interface-number [ slot slot-number ] \| local [ slot slot-number ] ] [ count ]
Display flood attack detection and prevention statistics for an IPv6 address.	display attack-defense { ack-flood \| dns-flood \| fin-flood \| flood \| http-flood \| icmpv6-flood \| rst-flood \| syn-ack-flood \| syn-flood \| udp-flood } statistics ipv6 [ ipv6-address ] [ interface interface-type interface-number [ slot slot-number ] \| local [ slot slot-number ] ] [ count ]
Display information about IPv4 addresses protected by flood attack detection and prevention.	display attack-defense policy policy-name { ack-flood \| dns-flood \| fin-flood \| flood \| http-flood \| icmp-flood \| rst-flood \| syn-ack-flood \| syn-flood \| udp-flood } ip [ ip-address ] [ slot slot-number ] [ count ]
Display information about IPv6 addresses protected by flood attack detection and prevention.	display attack-defense policy policy-name { ack-flood \| dns-flood \| fin-flood \| flood \| http-flood \| icmpv6-flood \| rst-flood \| syn-ack-flood \| syn-flood \| udp-flood } ipv6 [ ipv6-address ] [ slot slot-number ] [ count ]
Clear attack detection and prevention statistics for an interface.	reset attack-defense statistics interface interface-type interface-number
Clear attack detection and prevention statistics for the device.	reset attack-defense statistics local
Clear flood attack detection and prevention statistics.	reset attack-defense policy policy-name flood protected { ip \| ipv6 } statistics

10-Security

Configuring attack detection and prevention

Attacks that the device can prevent

Compatibility information

Creating an attack defense policy

Configuring a single-packet attack defense policy

Configuring a SYN flood attack defense policy

Configuring an ACK flood attack defense policy

Configuring a SYN-ACK flood attack defense policy

Configuring a FIN flood attack defense policy

Configuring an RST flood attack defense policy

Configuring an ICMP flood attack defense policy

Configuring an ICMPv6 flood attack defense policy

Configuring a UDP flood attack defense policy

Enabling the login delay

Displaying and maintaining attack detection and prevention

Intelligent Terminal Products

Product Support Services

Technical Service Solutions

Resource Center

Policy

Online Help

Become a Partner

Partner Policy & Program

Global Learning

Partner Sales Resources

Service Business

News & Events

Contact Us