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NICs will keep renewing the same IP address

Posted on 2004-08-19
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Last Modified: 2010-04-13
Hello There.

I have DHCP/DNS running on a Windows 2000 Server. There are 2 scopes handing out IP addresses.

My problems is this: When i physically bring a computer from one scope to the location of the second scope, I cannot renew a new IP address from the new location.

I have even removed the card and placed it in another machine, and it still pulls the same IP address.

If I statically set it to an IP address in the new location, it's fine.

I have gone into the DHCP area and deleted the entry, but that doesn't help. I just renews the same IP. There are no reservations in the scope.

There doesn't seem to be a pattern as to a certain type/brand of NIC.

WINs is not enabled on that scope.

Not sure what may be going on.

Thanks for any help.

-P
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Question by:pinger
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by:TASINetwork
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DHCP will store the last used IP info in the registry and tries to use the same info when it tries a renew (even if the lease has expired).  One thing that you might be able to try is to uninstall the NIC from device manager and then reinstall it.  You might want to check the registry first and see which NIC it is in the list (stored by a GUID), and after the uninstall, if that directory still exists, delete it, then reinsall.
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by:stlcards2004
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First are you sure the Ip address is not static on the workstationor that there is no reservation on any of the scopes for the MAC if not ,write down the IP address that it is using and shut that computer down make a reservation in DHCP with a made up mac address and give the reservation that Ip address that you keep leasing. Then boot up your computer and it will get a new Ip address. Then you should be able to delete the reservation.
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by:jdeclue
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Did you try doing a "ipconfig /release" "ipconfig /renew"?
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by:saito1
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what are the scopes ? scopes are for different nets ?
for example
 1. net ID : 172.16.100
 2. net ID : 192.12.15

if these two networks seperated by switch so the switch MUST be configured to enable VLAN options for these two networks. switch have to support BOOTP message specification. after you configure switch ports (two ports for two VLANs) then when a computer sends message to get IP address then switch send BOOTP message to DHCP and DHCP understand the message comes from which net then it gives and IP address according to network ID by switch port. finally you need to configure switch for VLANs.

hope this info helps.

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by:pinger
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YES! there are 2 different scopes AND on separate VLANS.

But I am not clear on what you suggest as the answer. The switches that separate them are all cisco 3550. One of the 3550's is routing between the 2 networks.
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by:jdeclue
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Try to review this article from Cisco, on how to configure the 3550 fors bootp.

J
http://www.cisco.com/warp/public/473/100.html
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by:pinger
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The 3550 that is acting as a router does already have the ip-helper address pointing to our DHCP server. There is a Windows 2000 server handing out DHCP to the 2 scopes.

My problem isn't that I'm not getting an IP address....it's the fact that when i bring a machine from scope 2 into scope 1 (the scope with the dhcp server), it absolutely will not let go of the IP address from scope 2. even removing the nic and putting it in another machines doesn't clear it - which makes it seem like the mac address is behind held somewhere  and the ip address from scope 2 is associated with it.

1) I have done release/renew
2) I have deleted the entry from DHCP

the only solution i have to use now is to statically set an ip from scope 1 - but that's not really an acceptable answer.
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by:saito1
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I believe the problem is your switch configuration. if VLAN is configured correctly then you don't have this type of problem. we have many customers that use VLAN configuration. I recommend you to check swicth configuration.
on DHCP just define 2 scopes each for one subnet.
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by:pinger
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does the port that has the W2K box running DHCP need to be a trunk port?

CISCO 3550 #1:
interface GigabitEthernet0/7
 description DIRECT CONNECTION TO W2K SERVER RUNNING DHCP
 switchport access vlan 3
 switchport mode dynamic desirable
_________________________________________

CISCO 3550 #2 (acting as router):
interface Vlan3
 description MAIN NETWORK VLAN
 ip address 192.168.200.1 255.255.255.0
 no ip redirects
 standby ip 192.168.200.4
 standby priority 200
 standby preempt
!
interface Vlan100
 description 2ND LOCATION VLAN
 ip address 192.168.50.3 255.255.255.0
 ip helper-address 192.168.200.100
 no ip redirects
 standby ip 192.168.50.1
 standby ip 192.168.50.11 secondary
 standby priority 200
 standby preempt
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saito1 earned 50 total points
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I don't make switch configuration. my network engineers make it.
jdeclue gave a link, did you read it ?  http://www.cisco.com/warp/public/473/100.html
and if it doesn't help refer your switch manuals about VLAN configuration..
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by:pinger
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yes, i did read the article. and yes, i do have (and have had) an ip helper address on the switch.
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