How to get a LAN to forget a mac address

[docfxit]

I have a home network.

1 xp pro sp2
2 xp pro sp1
1 98 se

I had an old xp pro sp2 named Desktop. It's no longer on my network. I have a new xp pro sp2 named Desktop. Something is remembering the old mac address with the old name Desktop and I am having conflicts with the new mac address associated with Desktop. How can I get my network to forget about the old mac address? By the way both Desktop machines had/have the same IP address. Is it the browser that remembers these things? I have a couple routers involved. One is a Sonicwall TZW. I have checked the arp table and the old Desktop mac address is not there. The arp timeout is 200min and the old machine has been gone for weeks. The other router is a Linksys BEFSR41 and I'm only using it for pass through. Is there a way to clear out what ever is remembering the old mac address?

Thanks,
docfxit

 

[aftertaf]

check in dhcp if you have areservaion with this old Mac address
c:\> arp
will show you the local MAC cache

Aftertaf
We shall prevail, and they shall not

 

[ChrisAC]

The "network" itself does not "remember" a MAC address. Each host on the network discovers a MAC address of a device that it needs to talk to using ARP. If a host has a MAC address in its cache that you need to remove then just use "arp -d 1.2.3.4", where 1.2.3.4 is the IP address of the box with that MAC address.

For example, I have the MAC address of a device on 192.168.3.7 which I want to remove.

C:\Documents and Settings\chris>arp -a

Interface: 192.168.3.100 --- 0x10004
  Internet Address      Physical Address      Type
  192.168.3.1           00-0e-38-e7-98-4a     dynamic
  192.168.3.7           00-08-da-50-81-b1     dynamic


C:\Documents and Settings\chris>arp -d 192.168.3.7

C:\Documents and Settings\chris>arp -a

Interface: 192.168.3.100 --- 0x10004
  Internet Address      Physical Address      Type
  192.168.3.1           00-0e-38-e7-98-4a     dynamic

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[BigShyBear]

One thing to try is to turn everything on the network off, including network attached printers, bridges, routers. In your case, I would turn both the Sonicwall and the Linksys BEFSR41 off for at least 1 minute then power them back up and see.

 

[docfxit]

Thank you both for the reply.
This is what I get:
C:\>arp -a

Interface: 192.168.2.8 --- 0x3
Internet Address Physical Address Type
192.168.2.1 00-06-b1-41-48-d6 dynamic

Interface: 192.168.1.71 --- 0x4
Internet Address Physical Address Type
63.211.210.221 00-06-b1-41-48-d6 dynamic
64.12.24.8 00-06-b1-41-48-d6 dynamic
64.12.26.35 00-06-b1-41-48-d6 dynamic
64.12.28.80 00-06-b1-41-48-d6 dynamic
64.12.161.185 00-06-b1-41-48-d6 dynamic
64.12.201.36 00-06-b1-41-48-d6 dynamic
65.54.179.228 00-06-b1-41-48-d6 dynamic
65.54.183.192 00-06-b1-41-48-d6 dynamic
65.54.239.20 00-06-b1-41-48-d6 dynamic
66.80.130.23 00-06-b1-41-48-d6 dynamic
66.216.70.167 00-06-b1-41-48-d6 dynamic
205.188.248.138 00-06-b1-41-48-d6 dynamic
207.46.0.32 00-06-b1-41-48-d6 dynamic
216.45.19.33 00-06-b1-41-48-d6 dynamic
216.155.193.174 00-06-b1-41-48-d6 dynamic

1. The IP address I'm having problems with is the interface IP 192.169.1.71. This IP address is what DHCP assigned to the VPN. So it's both an IP address of the VPN and a gateway. I don't understand why it's an interface. The VPN is showing the default gateway with two IP's. One is this IP and the other is the correct default gateway. I also don't understand why the address in your example after the IP is 0x10004 and in mine it's 0x4. I'm running this on XP Pro sp1. Is that correct or is my network honked up? I do understand all the remote IP addresses are from Trillian.

Does anything look strange to you?

Thanks,
docfxit

 

[ChrisAC]

I wouldn't worry about it. On my home PC it's 0x2.

I'm still not sure of your set up?

This IP address is what DHCP assigned to the VPN. So it's both an IP address of the VPN and a gateway.

The gateway for what? So this device is dual homed? Is this XP box the gateway for the network?

The VPN is showing the default gateway with two IP's. One is this IP and the other is the correct default gateway.

What's "the VPN"? Is this another box? Is it the XP box? What should the default gateway be? Are you talking about the default gateway for the VPN device (an internet router?) or the default gateway for the LAN hosts?

And what is your MAC address problem? What MAC/IP keeps appearing in the MAC table that you don't think should be there?

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[docfxit]

I'm not sure how to quote something. If this doesn't work please let me know.

Thank you very much to taking the time to respond.

>Snip
/Quote
I'm still not sure of your set up?

Quote:
This IP address is what DHCP assigned to the VPN. So it's both an IP address of the VPN and a gateway.


The gateway for what? So this device is dual homed? Is this XP box the gateway for the network?
/End Quote

No it's not the gateway for the network. The Sonicwall router is the gateway for the network.

/Quote
Quote:
The VPN is showing the default gateway with two IP's. One is this IP and the other is the correct default gateway.

What's "the VPN"? Is this another box? Is it the XP box? What should the default gateway be? Are you talking about the default gateway for the VPN device (an internet router?) or the default gateway for the LAN hosts?
/end quote

The VPN is a secure connection setup between this laptop over wireless to the SonicWall router (locally). The default gateway should be 192.168.1.254 for the LAN.


And what is your MAC address problem? What MAC/IP keeps appearing in the MAC table that you don't think should be there?

The IP that I am having trouble with is 192.168.1.71. This PC is producing events saying:
The name "WORKGROUP :1d" could not be registered on the Interface with IP address 192.168.1.71. The machine with the IP address 192.168.1.71 did not allow the name to be claimed by this machine.

I'm getting these events every 5min. Every time I get one all the Icons on the Desktop disappear, all the icons in system tray disappear, all xp os windows disappear, the Desktop icons are rewritten except for any that were changed since the last shutdown. Any changed icons are lost. Only some of the system tray icons are re-written. It takes a re-boot to get all of them back. I have attributed all of this to the event listed above.

Thanks,

docfxit

 

[ChrisAC]

So your machine should have the IP address 192.168.1.71 but it's also on the network on another machine? I think that you'll just have to track down the rougue machine on your network, or use a different IP address.

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[docfxit]

The machine that had the address 192.168.1.71 is no longer on the network. It hasn't been here for weeks. I can't use an alternate IP address because SonicWall created the VPN software so it would only allow creating a dynamic IP address through DHCP. Every time I recreate the SonicWall connection it uses the same IP address.

Thanks,
docfxit

 

[ChrisAC]

The machine with the IP address 192.168.1.71 did not allow the name to be claimed by this machine.

It looks like something else on the network has that IP address. I would take your machine off the network and then on another machine try and ping that IP address and then check the ARP cache to see if it has a MAC address for that IP address. It you see a MAC address then you would have to trace that machine.

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[docfxit]

Hi Chris,

That's a great suggestion. I turned my laptop off and tried to ping 192.168.1.71. It failed. I'm thinking something is messed up in the network inside this laptop. I did rebuild the winsock, TCP/IP. I did run SFC /scannow and did a repair install. It does have all the fixes loaded. One other thing that is strange is when I look at Network Neighborhood all I see is this one machine. I don't see any of the other machines on the network. The Browser service is started and it does negotiate to be the Master Browser. I can ping other machines and I can transfer files from other machines by name as long as they are in the hosts file.

Thanks for your thoughts,
docfxit