In Centos V7 you may use the “nmtui” to get access to the graphical network setting and follow the step to set the network parameter.
In the first menu by selecting Edit a connection you will have the list of the ETH port available for configuration.
then by selecting on of the port you can set all the IP, Default Gateway, DNS for that port.
after set all the value you can save and get back to the previous menu.
after setting the port setting you need make sure that the port is active and ready for use by selecting the Activate a connection.
you can check and change the port state by moving on the port. if the port is at the active state then you will see the deactivate option on the right side and if the port is deactive at the moment you will have activate option.
last setting the Host name which you can modify your host name by selecting the last option in the main menu through Set system hostname.
after save all changes to apply the new setting you will need to reload the network by below command.
systemctl restart network