I experimented. I disabled the ftp ports through the firewall and was still able to use ftp on IP address 127.0.0.1. Therefore, I can access the internet while developing. Also, when using two computers, I can use the client (the one using WinSCP) to gain access to the internet.
It would still be useful to access documentation at times when no internet is available (like at a customer site).
By the way, I've been using WinSCP for years. I run FileZilla Server on tester computers and WinSCP on data servers for automating file processing. I recently discovered that WinSCP has a .NET assembly for embedding the ftp interface inside a .NET program. This is the topic for which I need access to the documentation.
Thanks,
Hamilton Woods