syn flood attack prevention

0x00 backgroundSYN Flood is one of the most popular DOS (denial of service attacks) and DDoS(distributed denial of service attacks), which is a way of using TCP protocol defects to send a large number of forged TCP connection requests, This allows the attacker to run out of resources (CPU full load or low memory).0x01 CodeThe purpose of this article is to describe how to construct packet using Python.Use the raw socket to send packets. This program is

Protect Against SYNSYN attack is the principle of using TCP/IP Protocol 3-time handshake, sending a large number of network packets to establish the connection, but not actualEstablish a connection that eventually causes the network queue of the attacked server to be full and inaccessible to normal users.The Linux kernel provides several SYN-related configurations, with commands:sysctl-a | grep synSee:Net.i

analysis, it can be basically determined that hackers use the acquired machine to send SYN Flood attack packets containing 970 bytes of Application Data filled with "0" to the fixed host, in addition to the SYNflood attack effect on the server, it also consumes a lot of bandwidth resources at the Internet egress of th

SynAttackProtect and the recommended value is 2 Specifies the number of TCP connection requests that must be exceeded for triggering SYN flood attack protection threshold 5 At the beginning-> run-> type regedit, under the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters, The value name is tcpmaxportsexhausted and the recommend

be used as an NTP server, and the internal time of this server should be used for synchronization; 2. The legendary NTP Reply flood attack, theoretically, 600 UDP packets are returned. I captured the packet and calculated that a packet contains more than 400 bytes. When I captured the packet, it was about 488 bytes (the specific packet size was not fully confirmed ). If there are no network barriers and ne

　　1 SYN Flood attack introduction: Denial of Service (DoS) is an effective and very difficult way to defend against, it aims to prevent the server from providing services for users who normally access the server. Therefore, DOS poses a critical threat to enterprises and organizations that rely closely on the Internet to carry out their businesses.

Attack principle: SYN Flood is one of the most popular DoS (Denial of Service Attack) and DDoS (Distributed Denial of Service Attack) methods, send a large number of forged TCP connection requests, and send the first handshake packet (SY