What must be configured to allow SNMP traffic on ACl switches?

In ACI, management protocols like SNMP are governed by contracts. For out-of-band management, a specific out-of-band contract is required to permit SNMP traffic to and from the ACI devices, defining the allowed communication between management EPGs and the switch EPGs.

An out-of-band management interface defines the physical or logical pathway for communication but does not, by itself, permit specific traffic like SNMP without a contract.

An SNMP relay policy is used for forwarding SNMP traps from within the ACI fabric to an external destination, not for allowing SNMP access to the switches themselves.

An out-of-band bridge domain is a foundational component for out-of-band management, providing the Layer 2 domain, but it does not specify which protocols are allowed; that is the function of a contract.