Use iptables to set some security protection functions (1)

Article Title: Use iptables to set some security protection functions (1 ). Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.
Author: kenduest (xiaozhou)
It is often seen that someone uses the port scan software (ex: nmap) to scan others' ports in disorder,
Really annoying @_@
　　
Here we provide several methods through the new kernel mechanism of linux kernel 2.4 + iptables
To make some restrictions:
　　
# Nmap fin/URG/PSH
Iptables-a input-I eth0-p tcp -- tcp-flags ALL FIN, URG, PSH-j DROP
　　
# Xmas Tree
Iptables-a input-I eth0-p tcp -- tcp-flags ALL-j DROP
　　
# Another Xmas Tree
Iptables-a input-I eth0-p tcp -- tcp-flags ALL SYN, RST, ACK, FIN, URG-j DROP
　　
# Null Scan (possibly)
Iptables-a input-I eth0-p tcp -- tcp-flags ALL NONE-j DROP
　　
# SYN/RST
Iptables-a input-I eth0-p tcp -- tcp-flags SYN, RST SYN, RST-j DROP
　　
# SYN/FIN -- Scan (possibly)
Iptables-a input-I eth0-p tcp -- tcp-flags SYN, FIN SYN, FIN-j DROP
　　
This is intended for the use of scan software and the so-called Stealth mechanism to scan others.
You can discard these packets on the host without processing them. The other party will be stuck after scanning, or
Wait for the online timeout to continue working and prolong the scan time.