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300-170 · Question #52

You are configuration a group of web servers and you create a contract that uses TCP port 80. Which action allows an external Layer 3 cloud to initiate communication with the EPG that contains the…

The correct answer is D. Configure the EPG as a provider and L3Out as consumer of the contract. To allow an external Layer 3 cloud (L3Out) to initiate communication with an EPG containing web servers on TCP port 80, the EPG must be configured as the provider of the contract and the L3Out as the consumer.

Cisco Data Center Virtualization

Question

You are configuration a group of web servers and you create a contract that uses TCP port 80. Which action allows an external Layer 3 cloud to initiate communication with the EPG that contains the web servers?

Options

  • AConfigure the EPG as a consumer and L3Out as provider of the contract
  • BConfigure OSPF to exchange routes between the L3Out and EPG
  • CCreate a taboo contract and apply it to the EPG
  • DConfigure the EPG as a provider and L3Out as consumer of the contract.

How the community answered

(37 responses)
  • A
    5% (2)
  • B
    3% (1)
  • C
    14% (5)
  • D
    78% (29)

Why each option

To allow an external Layer 3 cloud (L3Out) to initiate communication with an EPG containing web servers on TCP port 80, the EPG must be configured as the provider of the contract and the L3Out as the consumer.

AConfigure the EPG as a consumer and L3Out as provider of the contract

If the EPG is a consumer and the L3Out is a provider, it means the EPG is initiating communication out to services in the external L3 cloud, which is the opposite of the requirement.

BConfigure OSPF to exchange routes between the L3Out and EPG

Configuring OSPF exchanges routes, but it does not define the security policy that permits or denies traffic flow between the L3Out and the EPG; contracts handle that.

CCreate a taboo contract and apply it to the EPG

A taboo contract explicitly denies communication, which is the opposite of allowing an external L3 cloud to initiate communication.

DConfigure the EPG as a provider and L3Out as consumer of the contract.Correct

For an external Layer 3 cloud (L3Out) to initiate communication to an EPG, the EPG must provide the contract (e.g., offering web services on TCP port 80), and the L3Out must consume that contract, thereby allowing traffic from the external network into the EPG.

Concept tested: ACI contract provider/consumer roles

Source: https://www.cisco.com/c/en/us/td/docs/dcn/aci/apic/6x/config/security/cisco-aci-security-configuration-guide-60x/m-contracts.html#Cisco_Concept.dita_2a792900-53e3-4f9e-bf33-ebcf826bfdf7

Topics

#ACI contracts#EPG#L3Out#external communication

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