Is it worth the trouble to map open ports in the firewall from some inconspicuous port number to the correct port number for a given service?
Or is it simpler and similarly secure just to present the actual port number required to the outside world? Client software these days is often pre-setup to just work if the default ports are used, and in many cases, people tend not to read instructions which often cause unnecessary disruptions and complexity.
This would be for a small to medium business situation. All software is kept up-to-date and internet security software installed on everything. If we need an example, let’s consider POP3 SSL @ 995, or FTP @ 21.