07-09-2012 02:54 AM - edited 03-07-2019 07:40 AM
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!
07-09-2012 03:03 AM
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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07-09-2012 03:21 AM
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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