How do I port forward a Rust Dedicated server?

So I switched to the C3000Z modem for CenturyLink and setup the internet so everything worked. I started port forwarding by setting the static IP for the device and did that correctly. So then I went to the Port Forwarding tab, selected the device by its name and the IP shown, typed in the starting and ending port, set the protocol to both TCP and UDP, and selected All IP Addresses for Remote Port and IP. After I started the server on the same port and the port checker I used said it was open I opened up the game to try and find it and it wasn't coming up. Then I viewed the steam servers, added the server as a favorite and when I refreshed the list it showed up as not responding. On the old modem, there was a port trigger setting to add the ports selected and we had to check some firewall settings like the 'Block Fragment IP Packets' setting. Be in mind this was an ARRIS modem given to us by spectrum. Are there any other settings I missed that had to be changed?