Can you port forward in your home router?
Can you open port 21 on your home router?
I'm not sure what you mean when you say "I have a router/modem connection where IP forwarding is turned off by my ISP."
I've never heard of an ISP doing this. They might block ports (although I confess I've never heard of that either) but I doubt they'd block forwarding.
For instance, they can't block http or you wouldn't be able to surf. If you can ftp out from your home/work, then you can ftp in. The traffic would hit your router and be forwarded by port from your router, not your ISP. I think you're confused and if you can't make sense of what we're saying, it might be worth your while to pay a professional to set you up.
I have two separate port forwards setup on my SOHO router at home. One for ssh and the other for RDC. When I go to ssh into my UNIX PC at home from work, it hits my router, my router sees it and forwards that port to the PC I specified in the forward. The same applies to my RDC sessions.
Unless your ISP completely blocks certain ports, there's no reason you can't do the same thing I have.
If your ISP does indeed block certain ports (like ftp) then I highly recommend you look at other ISP's and go with one that doesn't block ports.