IP Helper on Lagged Switches

[yasaman64]

                   Hi everyone,

I would really appreciate if someone could help me with this. I have two switches and lagged them together and the port channel passes default vlan and vlan 90. i have interfave vlan 90 with 10.10.2.2 ip address on the top switch and on bottom switch i created the vlan 90 and assigned it to port 10 and attached a thin client to port 10. now here is my question. on bottom switch with thin client is connected to and doesnt have a interface vlan, i created ip helper for the interface vlan of the top switch pointing to dhcp server that is on defaul vlan. is this a right thing to do? can i create ip helper for another switch's interface vlan if they are connected properly.

and my thin client cant get an IP, it can ping both vlans but cant ping dhcp server, what could be the issue?

Thank you so much.

[John Blakley]

Yes, it's the correct thing to do if your dhcp server resides in your "default vlan". (I'm assuming vlan 1.) You would need to have the port trunked between the 2 switches allowing both vlans over the trunk. If you have an interface vlan 90 on the "top" switch and that vlan is allowed over the trunk, when you connect your thin client and provision the port in vlan 90, the system should get an ip address. You will need a dhcp scope somewhere, server/switch/router, referencing the subnet that vlan 90 has (10.10.2.0/24) (again, I'm assuming that you're using 10.10.2.0 255.255.255.0.) and you'll need to make sure that you have enabled routing on the switch with "ip routing".

HTH,

John

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[yasaman64]

I didn this and still not working, i thought maybe the problem was that the interface vlan was on a different switch, i could not even ping the dhcp server although i could ping the interface vlan 1 ip from the thin client.

[John Blakley]

Can you post your switch config?

[yasaman64]

unfortunately i dont have access to the switches right now. i'll have to go on site..