1. 포트 확인 netstat 설치 [root@localhost ~]# yum install net-tools [root@localhost ~]# netstat -tnlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1044/sshd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1301/master tcp6 0 0 :::21 :::* LISTEN 10460/vsftpd tcp6 0 0 :::22 :::* LISTEN 1044/sshd tcp6 0 0 ::1:..