syn攻击 暂时解决

[root@xiaomu ~]# netstat -an | grep SYN | awk '{print $5}' | awk -F: '{print $1}' | sort | uniq -c | sort -nr | more

     36 109.70.69.59
      1 222.178.37.42
      1 218.108.85.59
      1 190.81.197.97
      1 190.116.88.11
      1 120.32.222.123

[root@xiaomu ~]# vim /etc/rc.d/rc.local
添加  然后保存
ulimit -HSn 65535

/usr/local/apache2/bin/apachectl start

#####

sysctl -w net.ipv4.tcp_max_syn_backlog=2048

sysctl -w net.ipv4.tcp_syncookies=1

sysctl -w net.ipv4.tcp_synack_retries=3

sysctl -w net.ipv4.tcp_syn_retries=3

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Syn 洪水攻击

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

--limit 1/s 限制syn并发数每秒1次

防端口扫描

# iptables -A FORWARD -p tcp --tcp-flags SYN,ACK,FIN,RST RST -m limit --limit 1/s -j ACCEPT

死亡之ping

# iptables -A FORWARD -p icmp --icmp-type echo-request -m limit --limit 1/s -j ACCEPT

#>iptables-save >/etc/sysconfig/iptables

进行查看，#iptables -L

ACCEPT tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,ACK/SYN limit: avg 1/sec burst 5

ACCEPT tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,ACK/RST limit: avg 1/sec burst 5

ACCEPT icmp -- anywhere anywhere icmp echo-request limit: avg 1/sec burst 5