08-14-2007 08:36 AM - edited 03-05-2019 05:53 PM
I have just installed a 6509 and put all o f the ports in card2 into VLAN 110. this has an ip address of 10.244.33.1 on card three is VLAN1 (Native) and this is on the 156.73.8.1 address. ON VLAN 1 is a DHCP server and on VLAN 110 there isn't but I have configured ip helper to go to a DHCP server on a remote network.
When I fire up a PC on VLAN110 it come back with a 156 address from the DHCP server on VLAN 1,rather than a 10.address from VLAN110. HOW is this happening? surely a DHCP address can't be passed from VLAn 110 to VLAN 1. IF I do a tracert from the PC it shows that it is directly connected to the 156 range. my head hurts....
08-14-2007 08:39 AM
Hi Tim
Is the DHCP server in the ip helper-address a different DHCP server from the one on vlan 1 ?
Can you confirm that the pc you start is connected to a port that is in vlan 110.
Could you post the relevant parts of your config ?
Jon
08-14-2007 09:06 AM
HI jon,
The DHCP server isn VLAN1 is a different one to the ones I am pointing the IP helper at. We are migrating the users from the 156 address range to a 10 address range. Yes the pC was on a port connected to VLAN 110.
interface GigabitEthernet2/2
description 1st Floor user
no ip address
duplex half
no snmp trap link-status
switchport
switchport access vlan 110
switchport mode access
spanning-tree portfast
interface Vlan1
description Legacy
ip address 156.n.n.1 255.255.240.0
ip ospf cost 3
standby 1 ip 156n.n.n
standby 1 timers 2 6
standby 1 priority 120
standby 1 preempt
!
interface Vlan110
description First Floor
ip address 10.233.44.1 255.255.255.128
ip helper-address 10.3.3.30
ip helper-address 10.4.4.33
Cheers
Tim
08-21-2007 05:05 AM
Okay, we've found the problem. I had left a port that shoul sdhave stayed in VLAN 1 and put it into VLAN 110 creating a bridging loop.
Doh!
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