Cannot access my Windows 10 FTP from the outside

[zylander]

I have a personal server at my home running Windows 10 and Im trying to setup an FTP server on it. I havent set one of these up in years and Im having trouble.

IIS is installed
FTP exception has been added to the firewall
Site has been setup and binded to the servers local IP
Port 21 forwarded to the server for TCP and UDP

I can FTP into the server from another local computer but cannot access it from outside my local network which means there must be something Im missing in my router but I just cant figure it out.

Im using an Asus RT-AC66U router and a DDNS. The DDNS is setup properly and works, I can access my server via remote desktop or VPN in from outside.

The cable modem/router supplied by Comcast has had its routing and forwarding functions disabled.

Any ideas/help is greatly appreciated.

 

[Fardringle]

Try using a non-standard port. Many ISPs (including Comcast) block common "server" ports on their consumer grade internet connections.

You'll need to configure the custom port number in the FTP site settings, the Windows Firewall, and the port forwarding on your router. Or, if your router supports port translation/redirection, leave the FTP site and Windows Firewall settings alone and just redirect the external port (say 2121 or whatever you choose) to internal port 21.

You can also try connecting directly to your public IP address instead of the DDNS address to see if it works that way..

 

[mikeymikec]

There's also fun to be had with the ftp data port(s). One step at a time though

 

[zylander]

Try using a non-standard port. Many ISPs (including Comcast) block common "server" ports on their consumer grade internet connections.

You'll need to configure the custom port number in the FTP site settings, the Windows Firewall, and the port forwarding on your router. Or, if your router supports port translation/redirection, leave the FTP site and Windows Firewall settings alone and just redirect the external port (say 2121 or whatever you choose) to internal port 21.

You can also try connecting directly to your public IP address instead of the DDNS address to see if it works that way..

Tried a non standard port, forwarding to the internal port.
Tried a non standard port for external and internal.
Tried connecting using my IP address instead of the DDNS.

Also tried forwarding port 20, still no luck.

I cant figure out what Im missing. I had an FTP server running on this same internet connection from Comcast years ago on a Server 2003 box just fine, cant remember what/if I did anything differently.