MySQL Master Slave Replication where master is not allowed to talk to slave
All that is required is for the slave to be able to establish and maintain a connection on the master's MySQL TCP port (3306 by default).  There is no need for the master to be able to establish a connection to the slave.  If you can telnet from the slave to port 3306 (or whatever port mysqld is running on) on the master, that should be all the networking you need.

There are a lot of guides, but the best one is the MySQL manual, see Chapter 17 Replication.