I have an old windows box which I have been trying to turn into a server to host some webpages and apps on. I have installed Ubuntu server and setup a static IP (192.168.0.xxx) for the box. Locally I can access the server over SSH, FTP and HTTP. I have also forwarded ports TCP: 22,80 and UDP: 21 for 192.168.0.xxx. However when I try to access the server remotely the page says it is not available. Any help would be greatly appreciated. Thanks!

So all three are being blocked by public IP. Does the router have any firewall features. Could try dmz on it just to see if that is the case. I'd do it only for a test.

I assume you do have proper external ip of router/modem. I'd also assume you have a single router/modem and not two devices.

My box is plugged directly into my only router. Also I know my external IP is right because when I go to that IP locally it works. It also doesn't work with DMZ.

The only thing I can think of is that my ISP is blocking ports.

Check your ISP service contract, you may find that under your contract terms you aren't allowed to "host" using your connection. If that is the case then the ISP may be blocking traffic on those ports higher up the "chain".

You can try turning your server firewall off, if that allows access then check your server firewall policies carefully.

Try setting your router up with port forwarding of non-standard ports and see if that works. For example set up port 8080 on your external IP to route to port 80 on your DMZ server and see if that works.