Hi, we have a couple of 3548's for our DC. They are connected via port-channel which is used for vPC peer link. Then there is a vPC going to a stack of 3750x.
Our dhcp servers are in VMware VMs running on ESXi connected to the Nexus'
I configured the dhcp snooping feature as follow on the NXs:
feature dhcp
ip dhcp snooping
ip dhcp snooping information option
service dhcp
ip dhcp snooping vlan 1,13-15
Then i trusted the ports going to the vmware boxes, and the port channel going to the other nexus
On the catalyst side:
ip dhcp snooping vlan 1,13-15
ip dhcp snooping information option allow-untrusted
ip dhcp snooping
ip dhcp snooping database tftp://my-tftp-server/dhcp-snooping.db
ip dhcp relay information trust-all
Then I trusted the port-channel going to the nexus' and on the ports composing the port channel
The problem seems to be that the NXs seem to block everything...
The catalysts should be fine: if do a dhcp requests from an access switch I see the requets beeing processed on the 3750x and being forwarded to the PortChannel to NXs:
008647: May 16 17:35:44: DHCP_SNOOPING: process new DHCP packet, message type: DHCPREQUEST, input interface: Te2/1/2, MAC da: 0050.5696.6e1a, MAC sa: 847b.eb4a.5205, IP da: 192.168.0.76, IP sa: 192.168.1.141, DHCP ciaddr: 192.168.1.141, DHCP yiaddr: 0.0.0.0, DHCP siaddr: 0.0.0.0, DHCP giaddr: 0.0.0.0, DHCP chaddr: 847b.eb4a.5205
008648: May 16 17:35:44: DHCP_SNOOPING_SW: bridge packet send packet to port: Port-channel5, vlan 1.
But nothing comes back. As soon as I disable dhcp snooping on the nexus everything comes back to life.
I even tried to run a dhcp client on the nexus's, just to put the 3750's out of the picture but it does not work anyway.
sh ip dhcp snooping statistics reports all 0s and sh ip dhcp snooping binding is empty.
I'm not very familiar with nxos and I don't know how to further debug
I'm running 6.0(2)A6(4)
Network schema is attached
