A, centos7 default is not started ifconfig, vi / etc / sysconfig / network-scripts / ifcfg-ens33, into ONBOOT = yes;
systemctl restart network reboot network; ip addr view ip address
Second, no default ifconfig command, yum install ifconfig will prompt no such command; you can use yum search ifconfig to find,
It will prompt, to install the net-tools.x86_64;
ifconfig to view ip address