Network Device using IP but can't ping it *** help!

By Levi_L ·
I have a network in place and I statically assign ip's throughout the network. All of a sudden, a device stops working and reports a IP conflict. When i ping the ip, it comes back dead. I do a mac address search and it also comes back dead. I used IP scan and it also says the ip is dead.
When I try to assign any computer that IP address, it says that it has been statically assigned to another device and cannot be used.

Does anyone have any ideas how I could find the device that is using the IP, even though it won't ping and comes back dead?

Many thanks

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Do you have a DHCP server

by NetMan1958 In reply to Network Device using IP b ...

anywhere on the network? It sounds like you have one and it's handing out IP's that overlap those you have assigned statically.

One thing you can do, is not use that ip on any machine. Then periodically try to ping that ip and if it responds check the arp table on your computer for the MAC that relates to that ip. Then go here:
and enter the OUI from that MAC. That might tell you the manufacturer of the machine using that ip.

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by Levi_L In reply to Do you have a DHCP server

I don't have any DHCP servers at this location. Nothing would be handing out IPs, which is why I'm so stumped.

Thanks for the recommendation though.

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Multiple IPs

by cypher.msix In reply to Network Device using IP b ...

This seems to happen to me quite often when dealing with devices that have multiple IP addresses. Consider a laptop with a wireless card, network interface, broadband internet adapter, and a vpn client.

Now consider having a hardline plugged into the NIC, the wireless connected to a wireless router, the broadband card connecting to the wireless internet service, and the vpn connecting to an external network. That's four friggin IP addresses...

Ever try to ping one? Sometimes it doesn't respond. In those situations, I'll tracert machinename and find the ip address that the DHCP is translating. Weird.

That sort of reminds me of what seems to be happening to you, but I can't narrow it down without knowing anything about your network.

Windows 2003? AD? What sort of devices are on the network? What range is the IP subnet that you can't find? Is that range classified for a certain device?

Some things to try:

net session
tracert suspectedmachinename
tracert ipaddress
arp -a | find ipaddress (i think you already did this though)

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by shasca In reply to Network Device using IP b ...

You assign static IP's but you don't document it in a spreadsheet as to What is assigned and to what kind of device?

Expect this to happen alot in the future too.

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No help at ALL!

by Levi_L In reply to Records

Clearly this is no help, and it you aren't going to be any help, keep your comments to yourself.

And to clarify, I just took over this position and no I don't have a spreadsheet for this location as we have 500 machines and I have no time to make one.
BUT... no machines are assigned IPs below 25 besides servers and I only have 4.

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Try these out to see if they cure your issues.....

Question: What Is an IP Address Conflict?

Answer: An IP address conflict occurs when two computers on a LAN (local area network) or the Internet have been assigned the same IP address. IP conflicts between two computers normally render either one or both of them unusable for network operations.
How IP Address Conflicts Happen
Two computers can acquire conflicting IP addresses in any of several ways:

* A system administrator assigns two computers on the LAN the same static IP address

* A system administrator assigns a computer a static IP address within the local network's DHCP range (dynamic IP range), and the same address is automatically assigned by the LAN DHCP server.

* A malfunction in the network's DHCP server allows the same dynamic address to automatically be assigned to multiple computers.

* An Internet Service Provider (ISP) accidentally assigns two customers the same IP address (either statically or dynamically).

* A mobile computer is put into standby / hibernate mode and then awakened later.

Note that other forms of IP conflicts can also occur on a network. For example, one computer may experience an IP address conflict with itself if that computer is configured with multiple network adapters. System administrators may also create IP conflicts by accidentally connecting two ports of a network switch or router to each other.
Recognizing IP Address Conflicts
On most Microsoft Windows computers, if you attempt to set a fixed (static) IP address that is already active on the local network, you will receive the following pop-up error message:

The static IP address that was just configured is already in use on the network. Please reconfigure a different IP address.

On newer Microsoft Windows computers having dynamic IP conflicts, you should receive a balloon error message in the Taskbar as soon as the operating system detects the issue:

There is an IP address conflict with another system on the network.

Sometimes, especially on older Windows computers, a message similar to the following may instead appear in a pop-up window:

The system has detected a conflict for IP address...

On Mac or Linux computers, a similar message will normally appear on screen.
Resolving IP Address Conflicts
Try the following remedies for IP conflicts:

1. For networks where IP addresses are fixed (statically assigned), ensure each local host is configured with a unique IP address.

2. If your computer has a dynamically assigned address, releasing and renewing its IP address can workaround IP address conflicts. See also - How to Release / Renew IP Addresses on Windows:
Renew IP Addresses on Windows XP | 2000 | NT

Follow these steps to quickly release and/or renew the Internet Protocol (IP) address of a computer running Windows XP, Windows 2000, or Windows NT.
Difficulty: Easy
Time Required: seconds
Here's How:

1. Click the Start menu button on the Windows taskbar.

2. Click Run... on this menu.

3. If the computer is holding a current IP address, type 'cmd' (without the quotes) in the text box that appears. A command prompt window appears on the screen.

4. Type 'ipconfig' (without the quotes) to view the status of the computer's IP address(es).

5. If the computer is holding a current IP address, type 'ipconfig /release' to let go of the address.

6. Type 'ipconfig /renew' to obtain a new IP address (whether or not the computer is holding a current address).


1. If it is not necessary to view the current IP addresses on a computer, simply type 'ipconfig /release' or 'ipconfig /renew' (without the quotes) in the text box that appears in Step 3.

2. To bring a computer back onto the network after moving it to a different location, or experiencing an unexpected outage, first release, then renew the IP address. Computers on DHCP networks often (but not always) re-establish network connectivity automatically.

What You Need:

* WinXP, Win2000, or WinNT
* IP network connectivity

3. If your home router is believed to have a faulty DHCP server causing IP conflicts on the home network, upgrading the router firmware may resolve this problem.

Please post back if you have any more problems or questions.
If this information is useful, please mark as helpful. Thanks.

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if using a static scheme and ping/-arp doesn't work,

by CG IT In reply to Network Device using IP b ...

there's only 1 way to find the offending device, that's to physically go to each one and check em.

you might try into a network mapping tool that queries devices and see if that turns up something. There's many available.

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