Ports required for PMM

Regarding Network - Percona Monitoring and Management, specifically the 7771 and 8428 ports, are these are like at tunnel or websocket? What I trying to understand is whether both the agent and server both listen on ports 7771 and 8428 or does the PMM server contact the agent (which is listening on 7771) and once established data can move back and forth but the server itself is not listening on port 7771. If it is the latter, does the 8428 work in just the opposite direction?

Hi @joe1 welcome to the Percona forums!
The default behaviour of pmm-agent is push based, meaning no listening ports are exposed on the local database server (the exporters are listening on localhost only). Push based also means that metrics are collected locally and then sent from pmm-agent to the PMM Server on encrypted port 443/tcp by default.

Thank you. Does that mean that the ports 7771 and 8428 are not needed then?

Correct, those ports are not required. Only open 443 from pmm client → pmm server