What must be configured to allow SNMP traffic on the APIC controller?

An out-of-band management interface provides the network connectivity for the APIC but does not, by itself, enable SNMP traffic without the necessary security policies.

A contract under the `mgmt` tenant is essential for defining the allowed protocols, such as SNMP, and their associated filters for out-of-band access to the APIC controller. Without this security policy, even with an out-of-band interface configured, SNMP traffic will be blocked by default ACI security mechanisms.

An SNMP relay policy is used for forwarding SNMP traps or queries from fabric devices to external destinations, not for enabling SNMP on the APIC controller itself.

An out-of-band bridge domain is a network construct that supports the out-of-band management interface, but it does not define the security policy to allow SNMP traffic.