This is an old revision of the document!
http://kb.parallels.com/en/123255
http://blog.parallels.com/2014/07/15/firewall-requirements-2x-remote-application-server/
http://kb.parallels.com/en/123707
Firewall rule names shown in title bars.
Port 20001 TCP open on remote RDS Servers before adding to 2X console in Backup Servers or Terminal Servers.