Advanced Authentication Clustering


Is there any better discussion of how advanced authentication works than is in the documentation ?

We have 4 nodes in 2 different firewall zones. I can see references to ports 5432,8080,9200, and 9300. Can somebody explain for me what the ports are and are they in fact required.

Imagine we have server1,server2,server3,and Server4. Server1 and Server2 and in the same  zone of the firewall. Server3 and Server4 are in a different zone. To allow these servers to be one cluster what ports will need to be opened between servers ?

Many thanks