RedHat Linux command to reload or restart network (login as root user):

# service network restart
OR
# /etc/init.d/network restart

To start Linux network service:
# service network start

To stop Linux network service:
# service network stop

Debian Linux command to reload or restart network:
# /etc/init.d/networking restart

To start Linux network service:
# /etc/init.d/networking start

To stop Linux network service:
# /etc/init.d/networking stop

Ubuntu Linux user use sudo command with above Debian Linux command:
# sudo /etc/init.d/networking restart

To start Linux network service:
# sudo /etc/init.d/networking start

To stop Linux network service:
# sudo /etc/init.d/networking stop