[pgsql-cluster-hackers] Streaming replication for security

My name is Márcio, from Brazil and I need help in understanding the streaming replication process.

I have a PostgreSQL data base hosted in an internal server. I need to replicate this database on Heroku for read only access, but I need to keep this Heroku instance synced with my internal server... I don't want to expose this PostgreSQL internal server to the Web...

What I understood in https://wiki.postgresql.org/wiki/Streaming_Replication is that standby will read data from master and not the other way... In this case, I will need to expose the internal database server to the Web via TCP, right?

If so, there is a way to make the master send the data to standby?

Ty all!

Márcio