please tell me how to change ip address randomly in ubuntu through terminal.
thanx in advance

What do you mean by "change IP randomnly"? You normally wouldn't do this since you need an IP in a certain Range with proper MAsk and Gateway for proper communications.

Do assign an IP via command line, you would use (for example):

ifconfig eth0 netmask
route add default gw
ifconfig eth0 down
ifconfig eth0 up

On Red Hat systems it is /etc/sysconfig/network-scripts/ifcfg-Auto_ethN (where N is the NIC you want to set - usually eth0). You would edit that file to change the static IP address (IPADDR=IPV4address, such as - you can't do this with DHCP) and then run the "service network restart". Bingo! Your address has now been changed.

For Ubuntu, you would go to /etc/NetworkManager/system-connections. Each NIC (hardware or WiFi) will appear as the file named "* connection N" where the leading asterisk is "wired" for a hardwire connection, and the trailing N is a number for the connection #, such as 0 for eth0, 1 for eth1, etc). I'm not sure what a WiFi would appear as since I am running this in a virtual machine without WiFi... :-)

In the appropriate file you will find the section [ipv4] and an entry "addresses1=YourIPV4Address;YourGatewayAddress". Example (from my VM):


So, change the IPV4 address (leave the gateway alone), and then, as mentioned above, restart the network services, except that for Ubuntu you would use "service restart network-manager" either as root, or with sudo. Oops. I mean "service network-manager restart"... :-) Danged keyboard keeps mistyping for me!