[DHCP issue] The clients in the non-vpn-default private network can't get IP address.

General ADcampus Fabric

After a customer creates a custom private network, users in the custom private network cannot get the address of the corresponding security group properly.

Step 1. Debuging dhcp relay all on the leaf.

*Oct  1 00:45:07:277 2021 BR-LEAF DHCPR/7/PACKET: -MDC=1; From 0.0.0.0 port 68, interface Vsi-interface27

    Message type: REQUEST (1)

    Hardware type: 1, Hardware address length: 6

    Hops: 0, Transaction ID: 1955856403

    Seconds: 0, Broadcast flag: 1

    Client IP address: 0.0.0.0   Your IP address: 0.0.0.0

    Server IP address: 0.0.0.0   Relay agent IP address: 0.0.0.0

    Client hardware address: 083a-xxxx-63dd

    Server host name: not configured

    Boot file name: not configured

    DHCP message type: DHCPDISCOVER (1)

*Oct  1 00:45:07:277 2021 BR-LEAF DHCPR/7/EVENT: -MDC=1; Is req pkt from tunnel, if 7024, if-type 111, port-if 7040, port-type 56

*Oct  1 00:45:07:277 2021 BR-LEAF DHCPR/7/EVENT: -MDC=1; Is req pkt from IPL, index 7040, bIsFromIPP 0

*Oct  1 00:45:07:278 2021 BR-LEAF DHCPR/7/EVENT: -MDC=1; Add relay agent option (32 bytes) to the packet.

*Oct  1 00:45:07:278 2021 BR-LEAF DHCP/7/ERROR: -MDC=1; Failed to send packet, ret -1, vrf 2 addr 10.8.94.12 if 0 cvlan 65535 svlan 65535 UnicastDstMac 0

*Oct  1 00:45:07:279 2021 BR-LEAF DHCP/7/ERROR: -MDC=1; Failed to send packet, ret -1, vrf 2 addr 10.8.94.11 if 0 cvlan 65535 svlan 65535 UnicastDstMac 0

Step 2. Checking the setting on the gateway of overlay service.

[BR-LEAF]int Vsi-interface 27

[BR-LEAF-Vsi-interface27]dis this

#

interface Vsi-interface27

 description SDN_VSI_Interface_27

 ip binding vpn-instance BR_VPN

 ip address 10.x.x.254 255.255.254.0

 mac-address 0000-0000-0001

 local-proxy-arp enable 

 dhcp select relay proxy

 dhcp relay information circuit-id vxlan-port

 dhcp relay information enable

 dhcp relay server-address 10.x.x.12

 dhcp relay server-address 10.x.x.11

 dhcp relay source-address interface Vsi-interface4094

 dhcp relay request-from-tunnel discard

 distributed-gateway local

#

return

[BR-Vsi-interface27]int vsi 4094

[BR-LEAF-Vsi-interface4094]dis this

#

interface Vsi-interface4094

 ip binding vpn-instance vpn-default

 ip address 10.x.x.129 255.255.255.128

 local-proxy-arp enable 

 arp proxy-send enable

#

return

Step 3. Notice the leaf is sending the DHCP relay packets with the source ip of interface vsi 4094, while the devcie is searching the routes in the vrf 2 which is the vpn-instance BR_VPN. However there is no routes to the DHCP server in the routing table of vpn-instance BR_VPN.

Adding a route in the vpn-instance.

BR_VPN. ip route-static vpn-instance BR_VPN 10.x.x.0 24 vpn-instance vpn-default 6.6.6.5 // 6.6.6.5 is the next hop to the DHCP server.