Duplicate IP address

Hello,



I have a very strange IP address conflict issue that has been bugging me for
a few weeks now.



I have a group of servers and a limited number of IP addresses available for
me to use.



I am trying to assign a new server one of my IP addresses, but I am getting
an IP address conflict. If I look at the network traffic as I am assigning
the IP address I can find the MAC address of the server that is answering
the ARP query.



I have located the server with the MAC address, but cannot find the IP
address that is in conflict anywhere in the registry or in the network setup
for this server. If I query the local ARP table, it does not list this IP
address.



I has also configured this server (for a very short period of time) as a
DHCP server to assign an IP address to another server I had lost contact
with. This was removed once I had made contact with this server.



I have tried all of the usual tricks to flush this IP address out of this
server (ARP -d, repair network adapter).



If anybody has any ideas, please let me know, as I am going to have to
assign this IP address to another server in the next few weeks.



Thanks for the help.

Graham

hi,
more than one ip's assigned to a nic ?
jk

No, I have checked all of that!

"Juergen Kluth" <jkluth-(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> hi,
> more than one ip's assigned to a nic ?
> jk
>

Dear Graham,

Thank you for your post.

If I understand correctly, when you manually assign an IP address to a
server (we call it serverA), you receive a message "Windows has detected an
IP address conflict". You have located the server (we call it serverB)
indicating that it has the same IP address. However, you cannot find out
the IP address in that serverB.

Before we go further, I would like to confirm the following information
with you:

1. When you ping that IP address, do you receive the reply?
2. Is there any virtual machine hosted in serverB?
3. I noticed that the ServerB was a DHCP server, is the role removed? Has
the database file been deleted?

In addition, please export the Windows IP Configuration (ipconfig /all)
from the ServerB for further research.

Thanks. I look forward to your response.

Sincerely,
Joson Zhou
Microsoft Online Support
Microsoft Global Technical Support Center

Get Secure! - www.microsoft.com/security
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HI
-you could do a ipconfig on the "guilty" maschine , may be it gives you the
answer
-you can look for "uninstalled" NIC's

-at last
you can open your registry and search for that ip
ONCE in a time (after repeating ethernal times the search) you might find a
hint to a nic that doesnt exist

jk








"Graham Webber" <(E-Mail Removed)> schrieb im Newsbeitrag
news:(E-Mail Removed)...
> Hello,
>
>
>
> I have a very strange IP address conflict issue that has been bugging me
> for a few weeks now.
>
>
>
> I have a group of servers and a limited number of IP addresses available
> for me to use.
>
>
>
> I am trying to assign a new server one of my IP addresses, but I am
> getting an IP address conflict. If I look at the network traffic as I am
> assigning the IP address I can find the MAC address of the server that is
> answering the ARP query.
>
>
>
> I have located the server with the MAC address, but cannot find the IP
> address that is in conflict anywhere in the registry or in the network
> setup for this server. If I query the local ARP table, it does not list
> this IP address.
>
>
>
> I has also configured this server (for a very short period of time) as a
> DHCP server to assign an IP address to another server I had lost contact
> with. This was removed once I had made contact with this server.
>
>
>
> I have tried all of the usual tricks to flush this IP address out of this
> server (ARP -d, repair network adapter).
>
>
>
> If anybody has any ideas, please let me know, as I am going to have to
> assign this IP address to another server in the next few weeks.
>
>
>
> Thanks for the help.
>
> Graham
>
>
>
>
>
>

Hello,

Thanks for the reply, and Yes this is the correct understanding of my query,
in answer to your questions:

1. I do not get a reply from the ping.
2. No virtual machines exist on ServerB.
3. The Scope has been removed, but I have not deleted any files relating the
DHCP.

Here is an edited version of the IPCONFIG/all results (Masking my IP
address)

Windows IP Configuration

Host Name . . . . . . . . . . . . :ServerB
Primary Dns Suffix . . . . . . . : mydomain.local
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : Yes
WINS Proxy Enabled. . . . . . . . : Yes
DNS Suffix Search List. . . . . . : mydomain.local

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Broadcom BCM5708C NetXtreme II GigE
(NDIS VBD Client)
Physical Address. . . . . . . . . : 00-1E-C9-D5-25-83
DHCP Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 192.168.XXX.1
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . :
DNS Servers . . . . . . . . . . . : 192.168.XXX.10

Ethernet adapter EXTERNAL:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Broadcom BCM5708C NetXtreme II GigE
(NDIS VBD Client) #2
Physical Address. . . . . . . . . : 00-1E-C9-D5-25-85
DHCP Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : xxx.xxx.9.134
Subnet Mask . . . . . . . . . . . : 255.255.255.248
Default Gateway . . . . . . . . . : xxx.xxx.9.129
DNS Servers . . . . . . . . . . . : 127.0.0.1


ARP Table (arp -a):

Interface: xxx.xxx.9.134 --- 0x10004
Internet Address Physical Address Type
xxx.xxx.9.129 00-09-e8-ee-ce-00 dynamic



The IP address I am trying to assign to ServerA is xxx.xxx.9.131.

The MAC address I am seeing in the network packets informing me of adapter
in conflict is the "Ethernet adapter EXTERNAL"

I have not added or removed any network adapters to ServerB, it still has
the same hardware configuration as when the OS was installed.

Many thanks for the help.
Graham


""Joson Zhou (MSFT)"" <v-(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Dear Graham,
>
> Thank you for your post.
>
> If I understand correctly, when you manually assign an IP address to a
> server (we call it serverA), you receive a message "Windows has detected
> an
> IP address conflict". You have located the server (we call it serverB)
> indicating that it has the same IP address. However, you cannot find out
> the IP address in that serverB.
>
> Before we go further, I would like to confirm the following information
> with you:
>
> 1. When you ping that IP address, do you receive the reply?
> 2. Is there any virtual machine hosted in serverB?
> 3. I noticed that the ServerB was a DHCP server, is the role removed? Has
> the database file been deleted?
>
> In addition, please export the Windows IP Configuration (ipconfig /all)
> from the ServerB for further research.
>
> Thanks. I look forward to your response.
>
> Sincerely,
> Joson Zhou
> Microsoft Online Support
> Microsoft Global Technical Support Center
>
> Get Secure! - www.microsoft.com/security
> ================================================== ===
> When responding to posts, please "Reply to Group" via your newsreader so
> that others may learn and benefit from your issue.
> ================================================== ===
> This posting is provided "AS IS" with no warranties, and confers no
> rights.
>

Hi Graham,

Thank you for the information.

Is NIC teaming used on ServerB?
Besides DHCP, what roles are installed on ServerB?

In addition, please check whether the "Proxy ARP" feature is enabled on the
related router/switch. Many routers or switches have the Proxy ARP feature
enabled to improve their performance. The switch/router simply answers
based on its ARP Table and records of who has what MAC address. This
feature may cause IP conflict error if the ARP cache on switch or router is
old. Please clear ARP cache on switch/router and disable the "Proxy ARP"
feature to test this issue again.

If the issue persists, I suggest:

1. Performing a clean boot in ServerB to temporarily disable all the third
party services.
2. Enable Netmon on ServerB to make sure that the ARP reply is sent from
the ServerB.

Thanks. I look forward to your response.

Sincerely,
Joson Zhou
Microsoft Online Support
Microsoft Global Technical Support Center

Get Secure! - www.microsoft.com/security
================================================== ===
When responding to posts, please "Reply to Group" via your newsreader so
that others may learn and benefit from your issue.
================================================== ===
This posting is provided "AS IS" with no warranties, and confers no rights.

Hi Graham,

How are you? I want to check with you about the status of this issue. Have
you tried the suggestions in my previous post? If there is anything further
I can do for you regarding this issue, please feel free to let me know.

Have a nice day.

Sincerely,
Joson Zhou
Microsoft Online Support
Microsoft Global Technical Support Center

Get Secure! - www.microsoft.com/security
================================================== ===
When responding to posts, please "Reply to Group" via your newsreader so
that others may learn and benefit from your issue.
================================================== ===
This posting is provided "AS IS" with no warranties, and confers no rights.