Tp-Link TL-SG3424P [173/259] Choose the menu network security dos defend dos defend to load the following page

With DoS Defend function enabled, the switch can analyze the specific fields of the IP packets and

distinguish the malicious DoS attack packets. Upon detecting the packets, the switch will discard

the illegal packets directly and limit the transmission rate of the legal packets if the over legal

packets may incur a breakdown of the network. The switch can defend a few types of DoS attack

listed in the following table.

DoS Attack Type Description

Land Attack The attacker sends a specific fake SYN packet to the destination Host.

Since both the source IP address and the destination IP address of the SYN

packet are set to be the IP address of the Host, the Host will be trapped in

an endless circle for building the initial connection. The performance of the

network will be reduced extremely.

Scan SYNFIN The attacker sends the packet with its SYN field and the FIN field set to 1.

The SYN field is used to request initial connection whereas the FIN field is

used to request disconnection. Therefore, the packet of this type is illegal.

The switch can defend this type of illegal packet.

Xmascan The attacker sends the illegal packet with its TCP index, FIN, URG and

PSH field set to 1.

NULL Scan Attack The attacker sends the illegal packet with its TCP index and all the control

fields set to 0. During the TCP connection and data transmission, the

packets with all the control fields set to 0 are considered as the illegal

packets.

SYN packet with its source port

less than 1024

The attacker sends the illegal packet with its TCP SYN field set to 1 and

source port less than 1024.

Blat Attack The attacker sends the illegal packet with its source port and destination

port on Layer 4 the same and its URG field set to 1. Similar to the Land

Attack, the system performance of the attacked Host is reduced since the

Host circularly attempts to build a connection with the attacker.

Ping Flooding The attacker floods the destination system with Ping broadcast storm

packets to forbid the system to respond to the legal communication.

SYN/SYN-ACK Flooding The attacker uses a fake IP address to send TCP request packets to the

Server. Upon receiving the request packets, the Server responds with

SYN-ACK packets. Since the IP address is fake, no response will be

returned. The Server will keep on sending SYN-ACK packets. If the attacker

sends overflowing fake request packets, the network resource will be

occupied maliciously and the requests of the legal clients will be denied.

Table 12-1 Defendable DoS Attack Types

On this page, you can enable the DoS Defend type appropriate to your need.

Choose the menu Network Security→DoS Defend→DoS Defend to load the following page.

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