How to port forward passive FTP from a router

Question

I have a TP-Link archer c7 that I use as an access point connected to my ZTE mf283 router. To my TP-Link ac I have connected a 250GB external HDD which I use as storage for my FTP server that I set up on my TP-Link router.

That works great on my local network but I wanna be able to connect to my router from outside my network so I tried portforwarding but I soon found that that I need to use passive FTP. Now I understand theory more or less but how can I set that up so that it works?

Solution

You need to:

• Forward the FTP control connection port 21.
• Forward the passive mode data connection port range (server-specific, usually configurable).
• Configure your FTP server with the external IP address of the router, so that the server reports the correct address to the clients.

Some references:

• My article on network configuration for FTP modes;

• My answer to Connection to FileZilla FTP server works, but directory listing fails.

Comments

[Admin]

As long as the port forwarding is correct, what works from inside works from outside as well. Meaning: No changes required except IP address which is your public IP address and the same port and same authentication if required.

[Martin Prikryl]

@MichaelBay That's not completely true for FTP - You need to configure the FTP server with the external IP address in addition to port forwarding.

[some user]

FTP is insecure and your username and password is sent via cleartext. This is especially dangerous when doing this from public network. I suggest you switch to SCP/SFTP ASAP, a lot easier to port forward too.

[WholesomeGhost]

@someuser I heard that suggestion a lot but how do I do that?

[some user]

I doubt your TP-Link supports SCP/SFTP. One alternative is use an open source router that runs DD-WRT which supports SSH and FTP. You can also get a dedicated device like pogoplug or raspberry pi to act as a server for your external HDD. And then you can port forward traffic to this device. Both solution takes time though.

[WholesomeGhost]

@someuser but is there a way to just set it up through regular ftp?

[Martin Prikryl]

FTP has a secure variant, the FTPS - FTP over TLS/SSL. Maybe your router supports that too.