Device getting assigned IP address from previous vlan

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jordan8thepie1

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#317883 23-Nov-2024 17:33

I recently changed vlans on a port on the network at work. Windows pc's that were connected to the default vlan won't get an IP Address from the new vlan.

The existing default vlan is serviced by a Windows Server DHCP. The new vlan has DHCP on the router.

If i connect another windows pc that has not previously connected to the default vlan it will get an IP correctly from the router. As soon as i connect any windows device to the default vlan It will keep the IP address from the Windows DHCP server.

Have tried using ipconfig /release and /renew and /flushdns and /registerdns and it did nothing. Also tried resetting the network adapter.

Our lease duration is set to 8 days on the windows dhcp server.

jordan8thepie1

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#3312222 23-Nov-2024 17:35

The Windows PC's also immediately lose network/Internet connectivity as well.

OmniouS

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#3312236 23-Nov-2024 18:58

Do you have a Superscope configured?

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richms

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#3312238 23-Nov-2024 19:00

Are you certain that they are totally isolated from each other and the windows DHCP server is not responding on that vlan as well?

Richard rich.ms

jordan8thepie1

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#3312240 23-Nov-2024 19:10

Superscope is not configured on the windows server

jordan8thepie1

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#3312248 23-Nov-2024 19:19

The IP Address and Lease time stays the same does not change.

Have noticed that it will immediately be assigned the same IP Address.

Also I can confirm that if I connect a windows PC that has not been ever connected to the vlan with the Windows Server dhcp it works fine and gets an IP address from the Router.

Connecting over Wi-Fi to network the vlan is assigned to works fine. it's only a problem on Ethernet.

OmniouS

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#3312258 23-Nov-2024 21:21

Do you have an IP helper set up on the switch to forward requests for your new vlan (or all vlans) to the Windows DHCP server?

What happens with a problematic client machine if you temporarily disable the Windows DHCP server service before plugging in?

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jordan8thepie1

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#3312260 23-Nov-2024 21:44

No ip Helper setup on the new vlan but we do on the existing vlan. I haven't tried disabling the windows server dhcp service.