Be careful when you are creating a DHCP relay agent and passing other DHCP traffic to the router but not destinated to it. By default DHCP snooping will be set if you activate relay agent or DHCP server on the junOS device.

We may see some DDOS for DHCP packets on these type of cases,

DDOS_PROTOCOL_VIOLATION_SET: Warning: Host-bound traffic for protocol/exception DHCPv4:bad-packets exceeded its allowed bandwidth at fpc X for 1 times, started at

DHCP traffic may be dropped due snooping.

NOTE: All DHCP packets passing through a DHCP unconfigured interface might be dropped. Enabling the DHCP relay or DHCP server feature also enables the DHCP snooping feature, which analyzes all DHCP packets received through any interface of the device (both DHCP configured and unconfigured interfaces) .

Interfaces not listed under DHCP settings are considered as unconfigured interfaces. Depending on the configuration, DHCP packets received on DHCP unconfigured interfaces are dropped.

We can add under forwarding-options no-snoop command to avoid this behavior.