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I use FTP (actually use ipSwitch WS_FTP) quite a bit to shuffle stuff back and forth to my server at my web hosting company with no problem.

But now I want to FTP to a computer that is inside a LAN. While I know the external I/P address of the router and I know that the internal computer running FTP services is I don't know how to configure this.

How is this done? Thanks, Gary

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migrated from Sep 3 '12 at 17:08

This question came from our site for system and network administrators.

You should use Port Forwarding / NAT feature provided in most of the routers. What it does is forwards all remote requests coming to External IP to configured LAN's IP/PORT and vice versa.

In your case, remote requests will come to your external_ip:21 address and router will forward requests to

Note : it would be easy to assist you if you have provided several things like type of internet you are using, router's company and model.

Below are websites you need in order to configure your router & to check whole setup.

To get router specific configuration for Port Forwarding.

To check whether specific port is open for internet.
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I'm assuming that your client is not on the same network as the server with address If the client is on the external network and there is not a route our some kind of proxy (a firewall or something similar) the I'm afraid it won't be possible. You'll have to transfer the files to the server you can ftp to and then find a way to get them to the other server from there. Either that or you well need to use a different transfer protocol that is open between your server and client if there are any.

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If you're coming from an outside address, you need to configure the router/NAT for port forwarding. If you don't have power to configure that router, you're out of luck, you won't be able to do it.

FTP is a complicated protocol, with two TCP streams. Old ftp actually had a connection from the FTP server going to the client, which complicates things through firewalls and NAT. Passive FTP helps this a bit - if you're going to have any luck at all, I'd make sure I could do Passive FTP on the FTP server.

FTP also sends name/password in the clear. It would be simpler (and more secure) if you were to use SFTP, which is basically the FTP command set run under the SSH protocol. It is a single port to forward, and the data - including your name and password - is encrypted.

If you do still go the FTP route, you'll need to configure two ports on your NAT for port forwarding (20/21) and make sure your ftp server supports passive FTP.

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Just enter the internal IP address in the connection dialog of your FTP client

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Yeah, he says it is behind a firewall that he can only see the internet IP of. – David Mackintosh Sep 4 '12 at 20:47
No! Must get there from a external location, hence the request must be encapsulated and the firewall/router must be told how – Alfabravo Sep 7 '12 at 17:40

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