PDA

View Full Version : How do I expire a DHCP lease?


BoOmEr2120
06-13-01, 09:10 PM
Hello,

I would like to know if there's a way to expire a DHCP lease without waiting for it to expire automatically. The reason I would like to know is because I have two IP addresses for my cable modem with two computers attached to the modem also. Now for one of those computers, I would like to change the network card, but since the DHCP lease won't expire for the previous card for several days, the new card won't be able to get IP information for that period of time.

Thanks!

YeOldeStonecat
06-13-01, 09:20 PM
Depending on what your cable providor uses....most of the newer cable setups use a Computer Identification name to get your IP address...so if your ISP uses that, you can simply swap your NICs, figure out which computer you want to get which IP by host name. Or cable ISPs using the older MAC address....you're stuck.

joepassavanti
06-13-01, 09:20 PM
actually dhcp is more forgiving than that. dhcp makes repeated attempts to renew itself beginning at half way through the lease periiod. you may renew or release your ip lease at any time. in win 95, 98, or me, go to start - run - type "winipcfg" and click ok. select your nic from the drop down menu and then click "release" from the buttons at the bottom. in nt or 2000, from a command prompt, trpe "ipconfig /release" or "ipconfig /renew". i hope that this helps.

BoOmEr2120
06-13-01, 09:23 PM
Thank you very much for the speedy replies. I will be sure to try that.

HalfLifer
06-13-01, 10:02 PM
Expires on its own.

YeOldeStonecat
06-14-01, 06:31 AM
Yeah but he's talking about cable, not an NT domain where winipcfg release/renew would actually do something. Around where I am, peeps have @home cable, and you're given a fixed IP address. My buddy has 2 IPs from @home, and each computer has the host name, C12345-a and C12345-b for example. Say C12345-a gets IP address 24.23.22.10 and C12345-b gets IP 24.23.22.11. He can winipcfg release/renew on those computers all day long, end result is computer A gets .10 and computer B gets .11. He can walk down the street to someone elses cable setup, change the host name on their computer to his, and guess what, he gets his usual IP address.

I have aDSL, and my lease expires monthly. I can release/renew all day long all week long, but I won't get a different IP address until my lease renews...and even then it's usually the same. I think my IP address has actually changed 3 times in 9 months.

Kip Patterson
06-14-01, 06:50 AM
For your situation, the IP address is not the issue. Turn off the computer and modem, replace the NIC, turn on the modem, then turn on the computer. If the system is configured to allow the changing of a NIC without notifying the ISP, it will boot up, obtain an IP lease, and connect automatically. If it doesn't, then you need to call your ISP and tell them you've changed your NIC, and you will need to give them the new MAC address.

Kip