In Linux, there are the commands to restart, start and stop the network. If you change the TCP/IP configuration such as ip address, net mask and gateway, the network need to be restart before it apply the new setting.
To restart Linux network service:
[root@server /]# service network restartor
[root@server /]# /etc/init.d/network restart
To start Linux network service:
[root@server /]# service network start
To stop Linux network service:
[root@server /]# service network stop