DHCPv6 Relay not working for Campus Fabric Clos
DHCPv6 clients through campus fabric Wizard in MIST , might not work with only default configs that wizard pushes.
Documentation about this is clear in 2 things that should be enabled for DHCPV6 relay to work ,
https://www.juniper.net/documentation/us/en/software/nce/nce-216-evpn-dhcp-relay/topics/example/nce-216-dhcp-relay-in-evpn-vxlan.html
There should be a dedicated loopback for the routing-instance VRF that should be the source of those packets when sending them through the ip-fabric to the COREs in ERB Campus Fabric or VGA configuration. This is due that lo0.0 will be VTEP tunnel endpoint
set protocols router-advertisement interface irb.x managed-configuration
set protocols router-advertisement interface irb.x prefix <ipv6 address >no-autonomous
set routing-instances CORP forwarding-options dhcp-relay dhcpv6 overrides relay-source lo0.1
Please note the lo0 and lo0.1 are loopbacks configured one is the vtep source , and other is the one sourcing the relay:
set groups top interfaces lo0 unit 0 family inet6 address <ipv6-address>set groups top interfaces lo0 unit 1 family inet6 address <ipv6-address>
this is to configure the IRB interfaces to send router advertisement messages with a default gateway address and the IPv6 prefix length information. The configuration enables the DHCPv6 Clients to identify the prefix length and the default gateway because the DHCPv6 Server does not provide the information. Also to source the lo0 dedicated as the COREs are lean devices.