查看有無建立iptables
sudo iptables -L建立一個新檔案 iptables.firewall.rules
sudo vim /etc/iptables.firewall.rules 內容如下
*filter
# Allow all loopback (lo0) traffic and drop all traffic to 127/8 that doesn't use lo0
-A INPUT -i lo -j ACCEPT
-A INPUT -d 127.0.0.0/8 -j REJECT
# Accept all established inbound connections
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
# Allow all outbound traffic - you can modify this to only allow certain traffic
-A OUTPUT -j ACCEPT
# Allow HTTP and HTTPS connections from anywhere (the normal ports for websites and SSL).
-A INPUT -p tcp --dport 80 -j ACCEPT
-A INPUT -p tcp --dport 443 -j ACCEPT
# Allow SSH connections
#
# The -dport number should be the same port number you set in sshd_config
#
-A INPUT -p tcp -m state --state NEW --dport 22 -j ACCEPT
# Allow ping
-A INPUT -p icmp -j ACCEPT
# Log iptables denied calls
-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7
# Drop all other inbound - default deny unless explicitly allowed policy
-A INPUT -j DROP
-A FORWARD -j DROP
COMMIT規則只開放 80(http), 443(https), SSH(22), ICMP 服務
啟用規則
sudo iptables-restore < /etc/iptables.firewall.rules最後是確保每次重開機都會載入這規則
sudo vi /etc/network/if-pre-up.d/firewall內容如下
#!/bin/sh
/sbin/iptables-restore < /etc/iptables.firewall.rules更改檔案權限
sudo chmod +x /etc/network/if-pre-up.d/firewalllinode官方教學： https://www.linode.com/docs/security/securing-your-server
其他小技巧
把80port轉到5601
sudo iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 5601
清除規則
sudo iptables -F -t nat sudo iptables -F