This is a first from me. Thus far all my experience has been within a LAN
with slower links to remote sites, but all connectivity was through a single
router. Now there will be remote sites that connect to the same node of
which my main router is connected to.

Are there docs or tids that indicate what ports need to be allowed through
the node router so all my servers can communicate with the master replica?
I need to install three servers at three different remote sites and like all
of you have limited time. I want to make the best decisions possible and
make efficient use of my time. Suggestions?