ifup command
ifup operates on network interfaces of a Unix/Linux system
ifup is used to change the status network interface to ‘up’ from a locked or down state
ifup operates and changes the administrative status of a network interfaces
ifup Examples
ifup eth0 — this will enable eth0 interface
ifup bge0 — this will enable bge0 interface
ifup -a — the -a switch tries to enables all interfaces present of the Linux/ unix system