Can not connect to friends Server

Hello, so I just created a dedicated Rust server for myself as well as one friend of mine. I start the server as normal, then proceed into the game where I enter ''client.connect localhost:28015'' which connects me to my server as normal. My friend tries to do ''client.connect [my external IP]:28015'' and they fail to join every time. I've tried everything I know like port forwarding but it still fails to connect. If you know how to solve this, that would be great. Thanks,SilentKnight202

 

if you have router you have to open ports 28215

 

how do i do that ?