ubuntu server 에서 방화벽 관리하는 방법
방화벽 추가
sudo ufw allow 22/tcp
sudo ufw allow 80/tcp
방화벽 삭제
sudo ufw delete <rule type> from <ip address> to any port <port number>
--> sudo ufw delete deny from 121.121.121.121
--> sudo ufw delete allow 80/tcp
--> sudo ufw delete deny from 121.121.121.121 to port 22
방화벽 활성화/비활성화
sudo ufw enable
sudo ufw disable
