refresh your ip configuration
are you refering to M$ winipcfg?
what distribution are you using?
do you only have one network card?
are you using a Local Area Network connection as opposed to a dial-up modem?
If the answer to all of the above is yes or LAN, you can try:
1. as root, open a terminal and type:
/sbin/ifconfig -a (to check your current conection)
dhcpcd -k [return] (trying to end your lease)
dhcpcd -n [return]
4. repeat step 1 (to ensure that your lease was renewed).
1.pump -i eth0 --status [return](check dhcp status on eth0)
2.pump -i eth0 --release [return](release eth0's dhcp IP)
3.pump -i eth0 [return](get dhcp ip for eth0)
1. as root, open a terminal and type netconfig (this is a console)
2. Would you like to set up networking? (select yes)
3. For a dhcp setup, hit the space bar (this should "gray out" all the static IP protocol fields and hit tab until OK is selected and hit return.