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IP Conflict

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22 replies

by skylermat

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I have a Win95 client running in an NT Domain. When the user starts the computer, it's giving them an error saying that there's an IP Conflict or bad name and and that you won't be able to access Network Resources,the messages also shows the IP address which has a conflict and the mac address of the nic. The DHCP is the one assigning the IP address. I've been experiencing this for more than 5 times now and the work around that i'm doing right now is to assign static IP address that is not included in the DHCP scope to that machine,but is there another work around that you can suggest coz i might be running out of static ip addresses in the future if this is going to happen often. Pls help..thank you.

22 replies

by gigelul

Delete only entries for clients that are no longer using the assigned DHCP lease or that are to be moved immediately to a new address. Deleting an active client could result in duplicate IP addresses on the network, because deleted addresses will beassigned to new active clients. After you delete a client's lease and set a reservation or exclusion, you should always use ipconfig /release on the client computer to force the client to free its IP address.

by gigelul

If you want, give this client a new IP address. At the command prompt on the client computer, type ipconfig /renew.

For Win9x clients use

by vh_s

Try to locate the problem computer. Shut down and plug the network cable out of the problem computer. And use other computer to login into the domain and ping the problem IP number.

This will give you a clue whether an existing IP was assigned into one of the computer.

This problem may arise out of two combination:
a. DHCP on, one of the computer in the network is using static IP and this static IP lies in the range of the IP scope addresses.
b. DHCP on, the server is certainly assigned static IP and this static IP is included in the DHCP scope addresses.

In both cases, define an exclusion in the DHCP spool.

vh_s

by alpha-male

I would turn off/disconnect the machine causing the IP conflict after noting its name and IP address.

Then I would run something like LANguard network scanner (free btw) on my local network. It will list what it detects on your LAN...machine names, IP addresses, open ports, usernames, shares, mac address, etc. From this, look for a match of machine name or IP. Once you spot it, take a look at what else it tells you about the offending device. It should give you plenty of clues with which to track down the problem child.

To get LANguard (an awesome product) go to www.gfi.com and grab the LANguard network security scanner.

Hope this helps!

by grimreality

Sounds like the first thing that you are going to have to do is keep a beter recording system of the pcs on the network along with the nics installed in the pc and what the name is along with the ip. Althoug from my experience you should not need names for the pcs on the network. But if you do then the naming convention for the pc should be something that would be able to guarantee, autonomy from all other pcs located in the same network. One good way to ensure that all names are unique is to use the mac address of the nic as the name.

by ken lei

i think it is a network problem,is it the problem will occur when the network traffic is very busy? because the pc can't get the free back of dhcp server in time, you must monitor the network traffic when the problem happens, or it may be cause by the network devices.

by wlbowers

Go into the server and find out what machine has that address. Go to that machine and enter winipcfg. Tell it to renew all. It should drop that address and assign another. Then if the new machine tries to use it it out to go.

Good Luck Lee

by bob.west

At the Win95 client PC, click Start>Run>; type in WINIPCFG and click OK. When the window opens, click release all. Shutdown and reboot. DHCP should assign a new non-conflicting IP address.

by pocono

If it's a bad name, you might want to check the DNS, just for chuckles, give it a new name, and see what happens....Peace...

by jeffrey952

You should also delete that address instance from the DHCP server. It sounds like someone switched their PC from DHCP to a static address which was within the scope of your DHCP addresses. by deleting that instacne and then going to the problem PC and using winipcfg, releasing and renewing the address, it will assign a new address.

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