Files on a server
Servers we host and servers the partner hosts, and what a partner is given.
A file connection is set up twice: one block for the server we receive from, and one for the server we send to. Each block says who hosts it and which protocol it speaks. Tick Same server both ways when one server does both.
When we host it
You choose the protocol and nothing else. The service mints the account name and the connection shows it, with the date it was created and the date it went live on the machine. The partner signs in to the file server for your environment, which is named on the onboarding letter together with its port.
An SFTP account signs in with a public key and an FTPS account with a client certificate, and you upload either one on the connection. Plain FTP is not offered on a server we host and the connection refuses it: the server requires TLS for every account, and it cannot be relaxed for one of them.
What the partner gets
Their own directory and nothing above it. They drop documents in in/ and collect documents from out/. A file has to stop changing before we take it, so a partner who uploads under a temporary name and then renames it is read at once.
One file may be at most 20 MiB, and the in/ directory may hold at most 512 MiB. A file above the size is deleted and a note saying so is written in rejected/, where the partner can read it. The account may hold four connections at a time.
A document we park for collection stays in out/ until the partner deletes it. Their delete is the only thing that says they have it: reading a file tells us nothing. Until that happens the message says stored, not transmitted.
When the partner hosts it
Give the address, the account, the password and the folder, and say how often we sign in. The shortest interval is five minutes, because a poll is a login on their server.
After fetch says what happens to a file we have taken: move it, delete it, or leave it. Leaving it means the next poll reads it again unless something else removes it.
FTPS through a firewall
Explicit TLS on port 21, and a range of passive ports at the same address. Allow the whole range as well as the control port, or the connection succeeds and the transfer stops. The range is on the onboarding letter. Our server certificate is renewed every 60 days, so trust the issuer rather than this one certificate.