title: port 8000 not enable even after enable it on firewall Ubuntu 18
body: <p>I'm stuck with a strange behavior with ubuntu 18 into digital ocean, I just created a droplet and didn't use DO firewall but try to enable port 8000 into server, like this:</p>
  
  <p><code>sudo ufw allow 8000/tcp</code></p>
  
  <p>When I check my port rules its ok, I mean its really what I need, there's even more (cause I also added udp) </p>
  
  <pre><code>sudo ufw status
  Status: active
  
  To                         Action      From
  --                         ------      ----
  22/tcp                     ALLOW       Anywhere
  80/tcp                     ALLOW       Anywhere
  443/tcp                    ALLOW       Anywhere
  80/udp                     ALLOW       Anywhere
  443/udp                    ALLOW       Anywhere
  8000/tcp                   ALLOW       Anywhere
  8000/udp                   ALLOW       Anywhere
  22/tcp (v6)                ALLOW       Anywhere (v6)
  80/tcp (v6)                ALLOW       Anywhere (v6)
  443/tcp (v6)               ALLOW       Anywhere (v6)
  80/udp (v6)                ALLOW       Anywhere (v6)
  443/udp (v6)               ALLOW       Anywhere (v6)
  8000/tcp (v6)              ALLOW       Anywhere (v6)
  8000/udp (v6)              ALLOW       Anywhere (v6)
  </code></pre>
  
  <p>When I run a flask service using port 8000 into server, something like this:</p>
  
  <p><code>FLASK_APP=app.py flask run --host=127.0.0.1 --port=8000</code></p>
  
  <p>I can get a response inside server, eg:</p>
  
  <p><code>curl 127.0.0.1:8000</code></p>
  
  <p>But when I try to do the same thing out site, I got refused connection, eg:</p>
  
  <p><code>curl IPSERVER:8000</code></p>
  
  <p>response:</p>
  
  <p><code>curl: (7) Failed to connect to IPSERVER port 8000: Connection refused</code></p>
  
  <p>I also check the port status using this service: <a href="https://www.yougetsignal.com/tools/open-ports/" rel="nofollow noreferrer">https://www.yougetsignal.com/tools/open-ports/</a></p>
  
  <p>And it says that port 8000 is closed, but I enabled it and there's no firewall on DO (I have one but I removed to test and it still not working) </p>
  
  <p>Does anyone know what could be? Ubuntu 18 has a another place to enable it? Should I restart the server before made these changes? </p>