DHCP: Replacing one IP with another

I started having some network problems today and was about to throw in the towel and start finding replacement hardware when I shut the machine down and notices the ping window I left open to the machine I just shutdown was still getting replies. That made my network problems a little clearer. The thing is, I get my IP Address from a DHCP server, so I am guessing someone set their IP address to one in the DCHP servers range. Is there a way to release the ipaddress I have and get a new one different than the one that is currently assigned to me. Usually there is a lease timer on these things and if I release and renew I will get the same IP address that I already have, which conflicts with someone on the network.

I am on a RHEL 5.x box and have tried releasing and renewing the IP address, but keep getting the same address ( which is conflicting with someone else on the network )

Rob Goodwin

Posted 2010-08-20T01:29:37.057

Reputation: 141

Answers

If you are in windows open cmd Start->Search->cmd.exe

ipconfig /release

ipconfig /renew

Should give you a new ip from the router with a different ip if the lease is handed out to another computer. The only issue is if that computer is setting it as a static. The router might not realize this and still give a lease for that ip. So your other option is setting your own static IP above the current range.

Unfundednut

Posted 2010-08-20T01:29:37.057

Reputation: 6 650

1A lot of DHCP servers will ping an address before assigning it. Hopefully his is one of them. – Karl Bielefeldt – 2010-08-20T01:46:42.177

yea, I have gone that route and seem to be getting the same ip address. I could not think of anything short of spoofing my mac address to get the server to give me something new despite what my lease timer states – Rob Goodwin – 2010-08-20T12:33:52.430

@Karl Bielefeldt: DHCP servers also store ipadresses and macaddresses so that when they log back in they get the same ipaddress. – Default – 2010-08-23T14:09:11.940

If you have access to your DHCP server (presumably, it's a router), you can access it (usually http://routerlogin.com works) and change the range of IP addresses that it hands out.

digitxp

Posted 2010-08-20T01:29:37.057

Reputation: 13 502