SSIS — RPC Server is Unavailable

Jon Morisi does some troubleshooting:

I just spent a long slog sorting out why I could not connect to my SSIS instance remotely.  I work in a very secure environment requiring network approval for any and all ports.  According to the following article, I was under the impression that a request to open incoming traffic on port 135, to a specific IP, would allow SQL Server Management Studio, on that specific IP, to connect remotely to SSIS:

https://docs.microsoft.com/en-us/sql/sql-server/install/configure-the-windows-firewall-to-allow-sql-server-access?redirectedfrom=MSDN&view=sql-server-ver16#BKMK_ssis

After opening port 135, I was receiving the error message in the title of this article:

If you find yourself in this situation, read on to see how Jon was able to solve the problem.