> ## Documentation Index
> Fetch the complete documentation index at: https://docs.intuitibits.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Frequently asked questions

> Frequently asked questions about Transfer.

Find answers to frequently asked questions about *Transfer*.

<AccordionGroup>
  <Accordion title="How can I initiate a download or upload using Transfer?">
    *Transfer* is a standalone file transfer server, not a client. The client is responsible for initiating the file download or upload request.
  </Accordion>

  <Accordion title="Can I use Transfer to update or restore the firmware of my device?">
    Devices that use TFTP, HTTP, FTP, or SFTP to update or recover their firmware operate in one of two modes. In one mode, the device acts as a server, and it expects a client to *upload* the firmware to it when indicated. In the other mode, the device acts as a client, and it expects a server that can be used to *download* the firmware from it.

    You can only use *Transfer* to update or restore the firmware of a device that acts as a client, expecting to *download* the firmware file from a server, in this case, *Transfer*.
  </Accordion>

  <Accordion title="How can I use Transfer with a network firewall?">
    #### TFTP

    To allow TFTP traffic through a network firewall, you must create two rules:

    * The first rule passes all UDP traffic from the client to your Mac. The client makes the first connection to the Mac on port 69, but it will then make a second connection on a *random* destination port.
    * The second rule passes all UDP traffic from your Mac back to the client, irrespective of the ports involved because *Transfer* will respond with a *random* source port.

    #### HTTP/HTTPS

    To allow HTTP or HTTPS traffic through a network firewall, you must add a rule that allows TCP traffic from the client to your Mac on port 80 for HTTP, or port 443 for HTTPS.

    #### FTP

    To allow FTP traffic through a network firewall, you must create two rules:

    * The first rule allows TCP traffic from the client to your Mac on port 21. If using PASV mode, you also must allow inbound TCP traffic on the [passive port range](/transfer/ftp-settings) configured in *Transfer* (50000-51000 by default).
    * The second rule allows TCP traffic from your Mac back to the client on the same passive port range.

    #### SFTP

    To allow SFTP traffic through a network firewall, you must add a rule that allows TCP traffic from the client to your Mac on port 22.
  </Accordion>
</AccordionGroup>

## See also

* [Troubleshooting](/transfer/troubleshooting)