ACI uses inter-fabric messaging (IFM) to communicate between the different nodes. IFM uses TCP packets, which are secured by 1024-bit SSL encryption, and the keys are stored on secure storage. The Cisco Manufacturing Certificate Authority (CMCA) signs the keys.
Issues with IFM can prevent fabric nodes communicating and from joining the fabric. We will cover this in greater depth in the SSL Troubleshooting recipe in Chapter 9, Troubleshooting ACI, but we can look at the output of the checks on a healthy system:
apic1# netstat -ant | grep :12tcp 0 0 10.0.0.1:12151 0.0.0.0:* LISTENtcp 0 0 10.0.0.1:12215 0.0.0.0:* LISTENtcp 0 0 10.0.0.1:12471 0.0.0.0:* LISTENtcp 0 0 10.0.0.1:12279 0.0.0.0:* LISTEN <truncated>tcp 0 0 10.0.0.1:12567 ...
