Network configuration files determine whether networking is started during the boot process. If started ,these files also determine whether address and routes are configured statically as documented, or dynamically with the help of commands like dhclient.
Basic networking configuration only confirms that systems can communicate through their IP addresses. But that is not enough. Whether you are pointing to systems such as server1.example.com or URLs such as www.mheducation.com, network configuration is not enough if the host-name or (FQDN) fully qualified domain name is not working.
The most common cause of network problems is physical. The section assumes you have checked all network connections.On a VM, that means making sure the virtual network card wasn't accidentally deleted on VM (virtual machine) or on the physical host.
Network configuration Files
# /etc/init.d/network
# /etc/sysconfig/network
# /etc/sysconfig/network-scripts/ifcfg-lo
# /etc/sysconfig/network-scripts/ifcfg-etho
# /etc/sysconfig/network-scripts
