I made a similar post in the Desk Api forum but thought this part of the community might prompt more discussion...

We require links on our Desk Portal to a secure FTP server for customers to download products, project files and documentation. There will also be a link to our FTP server where they can upload files. None of this data can be email attachments.

Customers will login to our Desk Portal using credentials established through the normal Desk "new user" signup process. Then besides being able to open/view tickets, knowledge base and community forums they will see a list of links on the right side of the page.

Initially we can manually maintain the customer accounts, virtual directories, etc on the FTP server (more about that below). We however want the customer to be taken directly to their authenticated directories on the FTP server and NOT be prompted to login again when they click one of the links. In other words a transparent single sign-on from their perspective.

Surely other Zoho desk (or even CRM) customers have similar requirements. We are not committed to using any particular FTP server product but would like to use something that has a reasonable cost for our company given that we do not need to support a very large number of concurrent connections. Frankly, I am surprised that Zoho itself doesn't offer a Secure FTP component to compliment its other products.

Once we have the above functionality operational we want to use Zoho Desk's webhooks to initiate Account/Contact and product related virtual directories on the FTP Server, which of course requires an FTP Server product that supports that functionality through it's own API's. We prefer to maintain the Account/Contact relationships in Zoho Desk and push that to the FTP server rather than the other way around.

Given that SOMEONE must have done this before, I hope the community can offer some experience based advice.