07-25-2012 07:01 PM - edited 03-07-2019 07:59 AM
Hello,
i have strange problem with MS DHCP server which i am unable to understand. One server hosts 3 DHCP scopes (data1, voice, data50). I also have 3 VLANs 1 (defualt) for data, 10 voice, 50 data. IP helper address is configured for VLAN 50 and 10.
DHCP scope for data 1 : 10.0.0.10-250
DHCP scope for data 50 : 172.16.0.10-172.16.1.250
I have HP 2910al-48G configured as default gateway, every VLAN has it's IP. That HP is connected to Cisco 3550, and 6 more Cisco 3500XL are connected to Cisco 3550. Now the problem
On some cisco 3500XL i configured port to be access port for vlan50. When i plug computer there i get the IP from data50 range and everything is great. Now when i plug the cable to some other port that has default configuration (so part of VLAN 1) i get the IP AGAIN from the DHCP range of VLAN50 (
172.16.0.10-172.16.1.250) . This is what is confusing me a lot and i don't know the explanation or how to fix it. When i disable data50 DHCP scope on the server and do ipconfing /release /renew i get the DHCP lease from data1 DHCP scope like i am supposed to.
Anyone have explanation for this? Thanks!
07-25-2012 09:31 PM
It will be helpful if you can give some diagram of the scenario.
Check out for any Native Vlan mismatch and also your helper address on the vlan interface.
Also paste switch port and trunk port configuration.
H2H
Bhargav
07-26-2012 02:49 AM
Hi,
here is the diagram.
http://img9.imageshack.us/img9/112/dhcpdiagram.jpg
HP
Port 48 i used as a trunk port.
vlan 1
name "Data"
untagged 5-14,16-48
ip address 10.0.0.254 255.255.255.0
no untagged 1-4,15
exit
vlan 10
name "Voice"
untagged 1-4
qos priority 6
ip helper-address 10.0.0.11
ip address 10.0.1.254 255.255.255.0
tagged 5-46,48
exit
vlan 300
name "WiFi"
no ip address
exit
vlan 40
name "BellSystem"
no ip address
exit
vlan 50
name "New_LAN_Subnet"
untagged 15
ip helper-address 10.0.0.11
ip address 172.16.0.254 255.255.254.0
tagged 48
exit
Cisco 3550
interface GigabitEthernet0/6
description link to HP2910al
switchport trunk encapsulation dot1q
switchport mode trunk
no ip address
interface Vlan1
ip address 10.0.0.253 255.255.255.0
!
interface Vlan10
no ip address
ip helper-address 10.0.0.11
!
interface Vlan20
no ip address
!
interface Vlan50
no ip address
!
interface Vlan100
no ip address
!
interface Vlan200
no ip address
!
ip default-gateway 10.0.0.254
ip classless
ip route 0.0.0.0 0.0.0.0 10.0.0.254
ip http server
Cisco 3500XL
interface FastEthernet0/40
!
interface FastEthernet0/41
!
interface FastEthernet0/42
!
interface FastEthernet0/43
!
interface FastEthernet0/45
description New_LAN
switchport access vlan 50
spanning-tree portfast
!
interface GigabitEthernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/2
!
interface VLAN1
ip address 10.0.0.250 255.255.255.0
no ip directed-broadcast
no ip route-cache
!
ip default-gateway 10.0.0.254
Message was edited by: Damir Reic
07-26-2012 08:36 AM
1 thing i nocited on DHCP server:
Superscope is configured with 10.0.0.10-250 and 10.0.1.10-250, i added 172.16.0.10-172.16.1.250 to that superscope and probably that could be the problem. I now created new scope for VLAN50 and soon i'll head out to location.
This might be the solution to my problem.
07-26-2012 10:29 AM
Always beware of native vlan issues when mixing vendors, if necessary create an unused vlan on the Cisco and mark it native.
Sent from Cisco Technical Support Android App
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide