It sounds like the networking guys are telling you that the CS is not exposed externally now. With a security server set up, there should be no direct connections from external clients to the connection server(s). You will need to allow various traffic between your security server and clients/desktops/connection server and mittim12's link covers that.
Also, the security server role has always existed with View - I suspect you're specifically talking about the PCoIP secure gateway feature, but that was introduced in 4.6 as well.
