Ubuntu Simple firewall UFW configuration record

I am operating under root, the normal user needs sudo permission
UFW Disable off
UFW Enable Open
This file can be closed IPv6
/etc/default/ufw
View Rules
UFW status
Example of adding a rule:

            ufw default allow outgoing            ufw default deny incoming                   ufw default deny   关闭所有外部访问端口            ufw allow ssh       ufw allow 22            ufw allow 80/tcp             ufw allow http/tcp            ufw allow 1725/udp            ufw allow 25:29/udp            ufw allow from 123.45.67.89            ufw allow from 123.45.67.89/24            ufw allow from 123.45.67.89 to any port 22 proto tcp             sudo ufw allow from 192.168.1.1 允许此IP访问所有的本机端口             sudo ufw deny proto tcp from 10.0.0.0/8 to 192.168.0.1 port 22 要拒绝所有的TCP流量从10.0.0.0/8 到192.168.0.1地址的22端口

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Log directory: Vim/var/log/ufw.log
sudo ufw logging on boot log
sudo ufw logging off log
sudo ufw logging Low|medium|high

1. Sep 15:08:14 The preceding values list the date, time, and host name of your server. The remaining important information includes:
   • [UFW BLOCK]: This is where the description of the recording event begins. In this example, it means that the connection is blocked.
   • In: If it contains a value, then the event is an incoming event
   • Out: If it contains a value, then the event is an outgoing event
   • Mac: Combination of destination and source MAC address
   • SRC: IP of package source
   • DST: IP for package destination
   • LEN: Packet length
   • TTL: Packet ttl, or time to live. Before the destination is found, it jumps between the routers until it expires.
   • PROTO: Protocol for packets
   • SPT: The source port of the package
   • DPT: Destination port of the package
   • WINDOW: The size of the packets that the sender can receive
   • SYN URGP: Indicates whether a three-time handshake is required. 0 indicates no need.

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Three to see the operating system port monitoring

Netstat-an | grep LISTEN | Grep-v ^unix "
Netstat-ntulp
Lsof-i-n-p

Ubuntu Simple firewall UFW configuration record