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New Member

IP address from incorrect scope is assigned from DHCP

Dear Experts,

I am trying to setup VLANs and most of configurations are working ok now except IP address assignment from DHCP.

Here are the details:

1. DHCP server Win2k8 R2 sits in VLAN 100

2. VLAN 100 (SVI address 192.160.100.1)

3. VLAN 120 ( SVI address 192.160.120.1)

4. VLAN 130 ( SVI address 192.160.130.1)

5. host computer in VLAN 120  cannot obtain correct IP from DHCP

6. host computer in VLAN 130  cannot obtain correct IP from DHCP

7. all host computers in VLAN 100 CAN obtain IP from DHCP

If any computer in VLAN 120 or 130 configured with manual IP address, then all works fine. It can reach internal servers and the internet without problem.

If the IP address is assigned automatically then any computer in VLAN 120 or 130 are obtaining  IP address (strangely!) from VLAN 100. Because switch ports that connected to the computer belongs to VLAN 120 or 130, the computer cannot reach internal servers and the internet with ip address from VLAN 100 .

All SVI interfaces for VLAN 100, 120 and 130 have ip helper-address option defined pointing to the DHCP server. No DHCP snooping enabled on all switches at this point. DHCP server have three scopes for the three different VLANs.

Please help me out! Thanks a lot!

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2 REPLIES
Purple

IP address from incorrect scope is assigned from DHCP

Hi,

Could you be clearer, if you assign an ip manually then you should not receive any dhcp address : 

If the IP address is assigned automatically then any computer in VLAN  120 or 130 are obtaining  IP address (strangely!) from VLAN 100

Regards.

Alain.

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New Member

Re: IP address from incorrect scope is assigned from DHCP

It turns out that the problem was in 'super scope' of Windows DHCP server.

When new normal scope is created for different VLANs then DHCP started handing out correct IPs to corresponding VLANs.

Thanks!

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