| Accessed from | sender's address | recipient's address | method |
|---|---|---|---|
| Internal network | internal | internal | direct transfer |
| Internal network | internal | external | direct transfer |
| Internal network | external | internal | forbidden |
| Internal network | external | external | forbidden |
| Internet | internal | internal | Sender receives an upload ticket |
| Internet | internal | external | Sender receives an upload ticket |
| Internet | external | internal | get confirmation from recipient |
| Internet | external | external | forbidden |