dhcp ip helper address question via FW, WAN

[queenscisco]

Hi 

I would like to check where we should terminate "ip helper address" for dhcp relay if dhcp server is located on DC while remote site (DHCP Client) is connected through VPN.

here is the simple path.

DHCP Client (vlan 3)-- Cisco TOP of Rack SW --Cisco Core SW --Juniper FW (L3 Vlan termination)--VPN GW -DC VPN GW--CISCO SW --DHCP Server

1. My question is our Cisco TOR sw is just L2 with multiple VLANS. i.e.: VLAN 2(mgmt), VLAN 3 (DHCP Client) but there is only one SVI with VLAN 2. My question is should we create SVI for VLAN 3 and add "ip helper address" under SVI Vlan3? 

2. Or no need to create SVI on TOR SW and add this config on either L3 Vlan termination on Juniper FW? 

Thanks

[Reza Sharifi · Accepted solution]

Hi,

Since the TOR is just layer-2 and you already have one SVI for vlan-2 on it, you don't need to add any more SVIs or IP helper address.  The helper address should be configured on the Juniper FW since it does the routing between vlans for you.

HTH

[queenscisco]

Thanks for your quick help!!