"There is an IP conflict with another system on the network"

[barnegattech]

Have server 2008; linksys BEF41SX end point VPN router and workstation with XP Pro.

One of the work stations gets a IP conflict message. DHCP is set up on the linksys router and disabled on the server. no one else has this IP that is in conflict. The DHCP table on the router just shows the workstation that is having the problem. The other 11 Workstations do not show up within the DHCP table, however they all have IP address and are logging in ok. Every computer is set up as dynamic with the exception of 3 printers which also do not have the IP address in question.
Removed the IP address from the DHCP table for this computer and had computer pull a new IP which was a different number, but still states during login that IP is a conflict but even with the new number no one else has this number as well.
Any ideas?

 

[tlcscousin]

Check to ensure only one network card in the computer. If the computer in question has tw network cards it could be a conflict with the one set to the other NIC. It can also if that computer at one time had another NIC and it was pulled because of an issue, still have the IP set statically on the old NIC settings which windows retains somewhere in its history

 

[rclarke250]

You could try turning off DHCP, and set a static ip address, to an address that is outside the dhcp block, and not the server,or printers. You can leave the DHCP enabled on the router, and all the other workstations, and the single machine will still connect. Or you can get a crossover, and connect it to a laptop and set 2 ip addresses as static and only change the last number. i.e. 10.10.10.1 and 10.10.10.2 they should be able to ping each other with no conflicts. If you are seeing errors during either of those tests, than the issue is in xp on the workstation. Or if you have any wireless devices grabbing the ip for some reason, if you have wireless.

Also the driver could be corrupt for the lan card, remove the device from device manager, And reinstall with a fresh driver.

The windows winsock could be corrupted to reset it at a command prompt type "netsh winsock reset catalog" no qoutes, and hit enter. This will set the windows network socket back to defaults.

 

[linney]

How many Network Adapters are on the machine in question? If more than one, does it make any difference if the unused Adapters are set to Disabled?

 

[barnegattech]

There is only one nic in each computer and no wireless. It seems that this is the only logged entry in the linksys befsx41 router client IP table. It has moved from workstation to workstation for what seems to be the same IP address. If I turn off the workstation in question and ping the conflicting address, it does not exist.

 

[barnegattech]

found out more information. Found a conflicting IP address. I had pinged the host name of another computer on the network and it came up with the conflicing ip addr. The only problem is is that conflicting computer is not even turned on. All workstation names are unique. computer d gets message about ip conflict for .102 and if I ping host name computer m, that also comes up with .102 but computer m is not even turned on.

 

[vacunita]

Does computer M support Wake on Lan? Technically that feature would require the NIC to be functional and to acquire an IP address when the machine is off, so it can be sent some network activity, to make the PC turn on.



----------------------------------
Phil AKA Vacunita
----------------------------------
Ignorance is not necessarily Bliss, case in point:
Unknown has caused an Unknown Error on Unknown and must be shutdown to prevent damage to Unknown.

 

[danomac]

Is it possible you have two NICs (in different machines) with the same MAC address? Happened to me once, took me a while to figure that one out...

 

[robmazco]

It might not even be another pc, what a about a rogue jetcard in a printer?

 

[barnegattech]

maybe. I set static IP addr on workstation and don't have the problem anymore but happened to another workstation. Set that workstation to a static ip and it still happens ramdomly to other workstations on the lan.
I starting to loose my trust in the linksys befvp41 router. Too many vpn issues at other clients and now this.

 

[BadBigBen]

It might not even be another pc, what a about a rogue jetcard in a printer?

or a VM, that runs on a client or server...


Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[barnegattech]

I suppose maybe a printer. this just started happening when I replaced the file server with a new one. Before DHCP was handled by the old server, now DHCP is handled by the BEFSX41 router (and yes, dhcp service is disabled on the new file server). prior to this we did not have this problem.

 

[goombawaho]

There is either something set to a static IP address on your network (router, printer server, printer, computer, server, managed switch, etc.)

OR you have a "rogue" device handing out DHCP addresses. You have to track it down item by item in your entire network. Search everywhere.

Search the registry of the system in question for that BAD IP address and see if it pops up. You could also content search all the files on the computer to see if the IP address is found somewhere.

 

[linney]

Does a Ping Command to the incorrect IP identify any machine or equipment?

Does the TraceRT Command to the incorrect IP lead anywhere?

Is there anything to be gained by exploring the Routing Tables?

Making Sense of Windows Routing Tables

http://www.windowsnetworking.com/articles_tutorials/Making-Sense-Windows-Routing-Tables.html

 

[barnegattech]

the stange thing is that the routing table does not show any of the other computers on the network. It only shows the computer have the IP problem.

 

[DTracy]

Check the names of everything in the lan and remember the character limit.

Has the router been named?

Make a list or generate a list of the ip's for everything including the router.

Check all the subnets and gateways.

Check the macs as per danomac suggestion. (ipconfig/all on each will show the names, ips, macs, subnets, gateways, and more)

 

[DTracy]

P.S. Do you have a domain or a workgroup? We may be able to get help from AD.

 

[barnegattech]

This one has me baffled. I had shut down all printers and workstations at the location. Just the server and one workstation was running. I still received the ip conflict message. For some reason the server is detecting a conflict. I received this message with my Linksys BEFSX41 router acting as DHCP and the DHCP service turned off on the server and also did it with the other way around with the DHCP turned off on router and turned on for server. Either way I received the message of IP conflict. This I would think would eliminate the router from the problem and I would think another workstation or printer on the LAN.
Finally I set the workstation having the conflict to static IP which eliminated the problem but 2 days later it cropped up for another workstation. It seems that when I set static IP on problem workstation, the problem just moves to another workstation.

 

[DTracy]

Is the conflicting IP inside or outside of the DHCP scope?

 

[linney]

Have you considered malware (on the Server) as a possible cause?