Source: http://www.krizna.com/centos/setup-network-centos-7/

When installing Centos 7, You may not able to connect network in that machine. This will happen because Ethernet interfaces are not enabled by default and need additional configuration.

Type “nmcli d” command in your terminal

# nmcli d

Recommended for beginners
Step 1 » Type this command “nmtui” to open Network manager and press enter after choosing ” Edit a connection” ( Use TAB for choosing options ) .

Command Line

Network interface config files are located in /etc/sysconfig/network-scripts/ directory. Open ifcfg-en…

nano /etc/sysconfig/network-scripts/ifcfg-en

Find

BOOTPROTO=none
ONBOOT=no 

and replace with

BOOTPROTO=static
ONBOOT=yes 

And add the below lines at the end of the file.

IPADDR=172.27.0.32
NETMASK=255.255.255.0
GATEWAY=172.27.0.1
DNS1=172.27.0.5File will look like below after changes.
TYPE=Ethernet
BOOTPROTO=static
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
NAME=enp0s17
UUID=f0c5b37d-299a-43cb-b74b-618bb252d129
ONBOOT=yes
HWADDR=00:0C:29:A1:B5:CC
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPADDR=192.168.1.10
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
DNS1=192.168.1.5

# systemctl restart network

Additionally you can use /etc/sysconfig/network file for hostname and DNS.
[bash]

HOSTNAME=server.krizna.com
DNS1=192.168.1.5
DNS2=8.8.8.8
SEARCH=domain.com