Questions about Firewalls.

I am looking into getting a firewall to protect that files we have archived. I have a very limited knowledge regarding firewall technology, so here goes.

Currently, we locally host an FTP server. All logins are through specific login/password accounts. If I were to enable a firewall, could I do it without having my customers change their login settings?

Also, I see some firewalls are listed as SOHO and some as SOHO/tc. What does this mean?


Mike