Useful Network commands in Linux

[kuldeep]

Useful Network commands
route

This command displays/change the routing table information.

$ route -n

Displays system routing information

$ route add default gw 192.168.10.1

Sets the system default gateway to 192.168.10.1
ifconfig

With this command the network interfaces can be configured overwriting the values on ifcfg-* files.

$ ifconfig

Shows the network configuration of all configured network interfaces.

$ ifconfig eth0 192.168.10.6

It assigns the ip 192.168.10.6 to the network interface eth0

$ ifconfig eth0:1 192.168.10.61

It creates a virtual network interface eth0:1 from eth0 with the ip 192.168.10.61.

$ ifconfig eth0 up/down

Activates/deactivates eth0 network interface
dhclient

This command is a dhcp-client that queries dhcp network configuration for the network interface to any active dhcp server.

$ dhclient eth0

Configures eth0 with the dhcp configuration retrieved.
system-config-network

This command launches a graphical application that configures the network interfaces, including wireless interfaces.
arp

The arp command manages the relation between IP address and MAC address.

$ arp -a
? (192.168.10.223) at 00:0c:29:4b:ce:ed [ether] on eth0
? (192.168.10.6) at 00:0c:29:21:f7:7f [ether] on eth0

Shows all arp entries cached by the system

$ arp -d hostname

Removes hostname arp entry

$ arp -s hostname MAC

Adds hostname arp entry with mac MAC
ethtool

Display/changes the network card settings.

$ ethtool eth0
Settings for eth0:
Current message level: 0x00000007 (7)
Link detected: yes

This commands verifies that there is a network wire plugged on eth0 network card.