ifconfig
ifconfig is a command-line tool used to configure, control, and query TCP/IP network interface parameters.
It allows users to configure an interface's IP address, netmask, and other settings,
as well as to activate or deactivate network interfaces.
Usage
ifconfig [-a] [-h] [interface]
ifconfig <interface> [inet] <options> | <address> ...
Parameters
-a: Display all interfaces which are currently available, even if down.
-h: Display help information.
interface: Specify the network interface to configure or query.
inet: Specify the use of the Internet Protocol. This is optional and mainly for compatibility.
Options
up: Activate the specified interface.
down: Deactivate the specified interface.
netmask <address>: Set the subnet mask of the interface to address.
broadcast <address>: Set the broadcast address of the interface to address.
mtu <N>: Set the Maximum Transmission Unit of the interface to N.
dstaddr <address>: Set the destination address for a point-to-point link to address.
pointopoint <address>: Configure the interface as a point-to-point link with the remote endpoint address.
multicast: Toggle the multicast flag for the interface.
allmulti: Toggle the all-multicast mode, controlling whether all multicast packets are received.
promisc: Toggle promiscuous mode, controlling whether all packets on the network are received.
arp: Toggle the use of the ARP protocol on this interface.
dynamic: Toggle the activation of DHCP client on the interface.
Examples
Activate an Interface:
ifconfig eth0 up
Set IP address and subnet mask:
ifconfig eth0 192.168.1.100 netmask 255.255.255.0
Display configuration of all interfaces:
ifconfig -a
Setting the MTU:
ifconfig eth0 mtu 1500