1.安装 iptables-persistent

`apt install -y iptables-persistent`

2.按需编辑 /etc/iptables/rules.v4 文件添加规则。

    #  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 ! -i lo -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 -m icmp --icmp-type 8 -j ACCEPT
    
    # Allow destination unreachable messages, especially code 4 (fragmentation required) is required or PMTUD breaks
    -A INPUT -p icmp -m icmp --icmp-type 3 -j ACCEPT
    
    #  Log iptables denied calls
    -A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7
    
    #  Reject all other inbound - default deny unless explicitly allowed policy
    -A INPUT -j REJECT
    -A FORWARD -j REJECT
    
    COMMIT

3. 重载规则iptables-restore < /etc/iptables/rules.v4

ipv6规则

#  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 ! -i lo -d ::1/128 -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 icmpv6 -j ACCEPT

#  Log iptables denied calls
-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7

#  Reject all other inbound - default deny unless explicitly allowed policy
-A INPUT -j REJECT
-A FORWARD -j REJECT

COMMIT