Accessing my FTP server on the internet

[eomotosho]

Good day all,

I just deployed FTP server on my LAN and I can access the server Locally. I need to access the same server over the internet . Kindly guide me through on how to achieve this. I already have a public IP on my router that connects the LAN to the internet.

Thank you

[davegibelli]

You need to NAT the FTP port on the device that has your public IP to the local IP of your FTP server. This is known as port address translation or PAT for short.

[Richard Burts]

To add a little bit to the answer provided - perhaps it would be helpful to be clear about the difference between static translation and dynamic translation. When we talk about PAT it is frequently in the context of dynamic translation. With dynamic translation when a device on the inside wants to send some data to the Internet it sends the data and the source address is the devices private IP address. At the router it will PAT and send the data with the source address now as the public address, and will use an assigned port number to identify the inside source so that when a response comes back the router will know how to translate the response.

That works fine when the data originates inside. But it does not work well when the traffic is originated from the Internet. When a device in the Internet wants to access the FTP server what destination address and port number would it use? To support access which originates from the Internet you would need a static address translation and not just the normal dynamic PAT translation.

HTH

Rick

[eomotosho]

Thanks a million Richard. I need to ask, is it possible to run both static and dynamic NAT on the same router.

Already, I have dynamic NAT configured on my router which all my LAN users access the internet with. Also the FTP server also access the internet since it is part of my Inside Local.

How do I now make the ftp server use that same public IP which my LAN users use to access the internet ?

[Richard Burts · Accepted solution]

Yes it is possible to perform both static address translation and dynamic address translation on the same router. Your config might look something like this

ip nat inside source static tcp 10.0.3.3 21 interface Gi0/0 21

HTH

Rick

[eomotosho]

Thanks guys. This worked

[Richard Burts]

I am very glad that it worked and that my suggestion was helpful. Thank you for posting back to the forum to tell us that it is solved. Thank you for using the rating system to mark this question as answered. This helps other readers in the forum to find threads that have helpful information.

HTH

Rick