Communication Issues in the Cisco C9516 ACI

[Translator]

Device Version: /bootflash/aci-n9000-dk9.14.2.7g.bin

Device Model: Cisco  C9516

Problem description:

As shown in the figure below, A cannot access B(any protocol), and after logging in to B and initiating a request from B to A(any protocol, we are pinging), both ends can communicate normally

When the ping fails, the leaf switches connected to A and B can learn the LOCAL endpoint information, and the coop table entries on the four spine switches are normal. The endpoint information of A and B can be found on the APIC controller.

Please help analyze the causes and solutions to the problem, thank you!

[AshSe]

Can you please draw diagram for a better understanding?

[Translator]

Can you please draw diagram for a better understanding?

[eric888888]

Hello, there is no firewall in the middle path. When B initiates to ping server A, server A can also ping server B.

[Translator]

Hello, there is no firewall in the middle path. When B initiates to ping server A, server A can also ping server B.

[Translator]

Hello, there is no firewall in the middle path. When B initiates to ping server A, server A can also ping server B. Can you tell me why？ Thanks！