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IP Address cache???

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10 replies

by m.sajjad.m

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I have an NT machine. Some days before I installed a second network card and assigned it an IP that was given by our ISP.
After testing connectivity I changed IP and set it to DHCP.
The IP that was tested on that machine is now assigned to my manager's machine.
Whenever my manager starts his machine, my NT machine says "a duplicate name has been detected on the TCP network. bla bla". And after that it stop responding any NetBIOS session from other computers while it can still access others.
I removed that card but problem is still there. Is there any kind of IP address cache that NT keeps. NT machine has sp6a installed.
This problem was there on an other machine. I am stuck because of this problem. Please help me to resolve this.

Sajjad
Pakistan

10 replies

by joseph moore

Do you run a WINS server service somewhere? WINS does keep IP address to machine name table, for client to use to resolve. And WINS entries can hang out for a long time.

by jarif93

This problem may be caused by a NetBIOS name conflict between the workstation and either another workstation with the same NetBIOS name, or a workgroup or domain with the same NetBIOSthe name to be claimed by this machine.

duplicate name NOT duplicate ip address
check LMHosts file.
use ping command.
try and change to different ip address
for testing

by m.sajjad.m

I think I have to give some more info about my setup.
I have 2 IP networks 192.168.x.x and 212.x.x.x.
I call 192.168.x.x my internal net and I call 212.x.x.x real net.
Real IPs are given by our ISP.
My NT machine is on 192.168.x.x net. I assigned it a 212.x.x.x IP. Then I removed that IP from that machine and assigned it to my manager's XP machine. Now my NT machine has only one NIC with 192.168.x.x IP.
Whenever my manager starts its machine that has only 212.x.x.x IP, my NT machine gives that non-sense error and stops responding for NetBIOS. While still accessible using IP. And it can connect to net using NetBIOS.
This is very strange and totally non-sense. But it is happening and I am stuck. I have to restart my NT machine each time after my manager's machine.

by pctech

From what I am reading, the problem is not with the IP addresses, per say, but with the computer names. "a duplicate name has been detected on the TCP network. " This error indicates that you have two computers with the same name on the same network. With one computer using an IP address of 192.168.x.x and the other using 212.x.x.x, it is possible that they are on the same subnet. A 192.168.x.x IP address has a network ID of 192.168.0.0. The minumum netowrk ID is 192.0.0.0 and a maximum network ID of 223.255.255.0. Still, I am at a loss of how rebooting the NT machine would resolve the problem and it is not resolved until after the reboot. What I would check is to assure that you do not have identical computer names on the network. I would also check the LMHOST files. This is what the error indicates.

I hope this helps you.

by m.sajjad.m

Dear, all these tips are obvious to any win net admin (I think so :) ). This problem is totally non-sense and the most disgusting fact is "it is happening". There is no logic of this error. I was told by some one to clear ARP cache of all my network devices (router,switches etc). But it also did not work. According to my (non-sense) view, IP is stored on NIC. The other place may be that XP machine. But where to check on NIC and on that XP machine.

by dotcomma

Computers have the ARP cache (MAC address <-> IP address) and the DNS cache (IP <-> DNS name) and the NetBIOS cache (IP <-> NetBIOS name), but those are emptied when you reboot, so that shouldn't be the problem.
What I would try first is completely de-installing the TCP/IP stack and the NIC (unless it's a NT4 server, then you need to install the loopback device before you reboot). I think the NT4 box has the offending IP address/NetBIOS name still in its registry and deinstalling NIC and stack is the easiest way to get rid of it.

Monika

by m.sajjad.m

Dear all, the problem is resolved with a non-sense event. My proxy server (wingate 4.5.2) crashed one day and after I restored it, this problem is gone.
Thanks for all of you to take your time for me.
Regards,

M.Sajjad
Pakistan

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