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DHCP troubleshooting on firewall located gateway

Hi All,

I am having a weird problem with DHCP, I have this Cisco WLC which has its gateway located on the firewall. And since it is a Cisco WLC, it has its own SVI which points to the DHCP server. Before, the DHCP relay was configured on the firewall since it holds the gateway IP, but due to some problem with the upgrade (which affects our DHCP),  we  have DHCP proxy mode enabled on the WLC and DHCP was working again properly.

Now here is the part I need help for, I have configured another VLAN whose gateway is also on the FW. And this particular wired VLAN cannot get IP from our DHCP server. Im not particularly good on DHCP process, but what I used to do is just configure "ip helper address" on the SVI (Gateway). My problem was the GW is on the firewall. DHCP server is on another VLAN and connected to the core, while the client was connected on the distribution switch, which is also connected on the core.

As for troubleshooting, I have configured a SVI on the distribution switch to check if it can reach the DHCP server, and it can successfully. I have tried to create a local DHCP on the core switch for this new VLAN (202) and SVI with IP on the same subnet and I still cannot get IP from switch DHCP. But when I put the SVI on the distribution and create the DHCP scope on the distribution switch, the client immediately got an IP.

So my question is what is the difference on the setup on wireless clients whose APs are connected on the same distribution switch (different vlan of course), with the client on a different vlan but on the same distribution switch? they are using the same DHCP server.

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