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resolve4200

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Vlan - IP address issue-

Having problems swapping PCs on known good network connections-
1)PC will be up and running, put another one in its' place and the PC shows limited network connectivity.
It will have an IP 169.254.x.x
If we connect the original PC back, it will be on the network with its' original IP.
2) Even with a new imaged PC, it looks like it is joining the domain but it doesn't.
After the reboot, it is in WorkGroup and has the IP 169.254.x.x
These problems have occurred on at least 4 PCs on the 2nd fl and 1
***If the network equipment configuration hasn't changed, it is possible that something must be wrong with the Vlan configuration or the DHCP configuration for the servers on the vlans

I checked two switches - bt2e-a and bt2e-b (where 2 of these pcs were connecting). Both ports were on vlan202 (one on each switch). On bt2e-a, I counted over 200 devices on vlan202. bt23-b had a large number of devices on its vlan202. I moved both of these device ports to vlan1101 and they picked up new IPs just fine. I believe in these cases, the DHCP allotted addresses for these vlans was very close to being full, and when one of the computers was taken off the network, it's IP was quickly taken up by other devices seeking IPs on the same vlan, thus preventing the new device from obtaining new IPs.

Does anyone have any other thoughts regarding the ip address allocation by the dhcp server
Vlan 202 is spanning across the trunk
Vlan1101 is local on the switch.
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giltjr
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What is the DHCP scope and network mask being used on VLAN 202?

Does the DHCP server have a different scope and mask when the requests come from VLAN1101?  Assuming that you are forwarding bootp requests from VLAN1101 to your DHCP server.
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ryan80

It looks like your DHCP scope could be full. That would fit the symptoms that you are describing. Look at you DHCP server and see what is free. If that is the case then you need to increase the scope or move machine to a different subnet.
Are you in charge of the switches?

It could also be a security feature on the switches, like mac-move or mac-limit.
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ASKER

yes the scope has 250 addresses available with a few reserved for printers. there is no mac security as far as I know. But I can ask the field tech to call me if and when it happens then I may be able to get more information.  I was wondering if someone had come across this type of behaviour... reason I posted this question  is that when the original PC is back at the port it obtains the IP then why would the new replaced pc fail to get the same IP. It is possible that the lease has not expired and hence the DHCP server fails to allocate the same address?
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giltjr
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Give the PC a static IP address and then see if you can ping something. If you can it is not port security.

From what you have described it is either the DHCP scope is out or port security.

Since you mentioned that your scope was pretty full, I would stick to my first guess and say look at the DHCP scope first.