SYN attack processing

For several links of Syn attack, the corresponding processing methods are proposed:

Mode 1: Reduce the number of Syn-ack packets (default is 5):

sysctl-w net.ipv4.tcp_synack_retries=3 sysctl -w net.ipv4.tcp_syn_retries=3

Method 2: Use SYN Cookie technology:

sysctl -w net.ipv4.tcp_syncookies=1

Mode 3: Increase the backlog queue (default is 1024):

sysctl -w net.ipv4.tcp_max_syn_backlog=2048

Method 4: Limit the number of SYN concurrency:

iptables -A INPUT -p tcp --syn -m limit --limit 1/s -j ACCEPT --limit 1/s

SYN attack processing