Question

connect() failed (111: Connection refused) while connecting to upstream

Posted on August 14, 2019
Let's Encrypt Ubuntu 18.04 Nginx API DigitalOcean
Asked by 243261243130244176524b46303274

Hi all,

Followed this tutorial to get Let’s Encrypt working on my Nest.js/Node server.

Everything works - running sudo nginx -t returns:

nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: configuration file /etc/nginx/nginx.conf test is successful

However, accessing my domain gives me a 502 Bad Gateway error. Specifically (from /var/log/nginx):

15004#15004: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 77.98.141.183, server: ww2.zone, request: "GET / HTTP/2.0", upstream: "http://127.0.0.1:8000/", host: "ww2.zone"

Here is my /etc/nginx/sites-available file:

Default server configuration
server {
    listen 80;
    listen 127.0.01;	
    listen [::]:80 default_server ipv6only=on;
    return 301 https://$host$request_uri;
}
server {
    # Enable HTTP/2
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name ww2.zone;

    # Use the Letâ€™s Encrypt certificates
    ssl_certificate /etc/letsencrypt/live/ww2.zone/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/ww2.zone/privkey.pem;

    # Include the SSL configuration from cipherli.st
    include snippets/ssl-params.conf;

    location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-NginX-Proxy true;
        proxy_pass http://localhost:8000/;
        proxy_ssl_session_reuse off;
        proxy_set_header Host $http_host;
        proxy_cache_bypass $http_upgrade;
        proxy_redirect off;
    }
}

And my server is within a git Repo within home/username.

The code to listen on the port is: await app.listen(process.env.PORT || 5000);

This used to be process.env.PORT || 80 but that would throw:

Error: listen EADDRINUSE: address already in use :::80

Any ideas? Pulling my hair out atm.

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Bobby Iliev

Site Moderator

• August 14, 2019

Accepted Answer

Hello,

You can only have 1 service listening on 1 port. So as you have Nginx listening on port 80 at the moment, you can not have your Node on the same port.

Also as you currently have your Nginx set to work as a reverse proxy for port 8000, what you could do is to just set Node to listen on port 8000.

This would fix your 502 error.

Here is a link to an answer on how to troubleshoot common Nginx problems:

https://www.digitalocean.com/community/questions/how-to-troubleshoot-common-nginx-issues-on-linux-server

Here is also a quick video demo on how to do that:

Hope that this helps! Regards, Bobby

andersonfrfilho • May 23, 2020

I have the same problem, when trying to access the nginx test page

2020/05/23 17:03:43 [error] 9037#9037: *28 connect() failed (111: Connection refused) while connecting to upstream, client: 179.126.139.213, server: hellonode, request: "GET /favicon.ico HTTP/1.1", upstream: "http://127.0.0.1:3000/favicon.ico", host: "165.22.43.156", referrer: "http://165.22.43.156/"
2020/05/23 17:03:43 [error] 9037#9037: *27 connect() failed (111: Connection refused) while connecting to upstream, client: 179.126.139.213, server: hellonode, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:3000/", host: "165.22.43.156"

run the comand netstat -plant

root@know-how-cloud:/# netstat -plant
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 165.22.43.156:3333      0.0.0.0:*               LISTEN      6385/node /home/dep
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      9029/nginx: master
tcp        0      0 127.0.0.53:53           0.0.0.0:*               LISTEN      722/systemd-resolve
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      926/sshd
tcp        0      0 165.22.43.156:22        179.126.139.213:5270    ESTABLISHED 8011/sshd: root@not
tcp        0      0 165.22.43.156:37592     161.35.127.202:25060    ESTABLISHED 6385/node /home/dep
tcp        0    340 165.22.43.156:22        179.126.139.213:1979    ESTABLISHED 5495/sshd: deploy [
tcp        0   1081 165.22.43.156:22        112.85.42.195:41424     FIN_WAIT1   -
tcp        0      0 165.22.43.156:22        222.186.42.7:61212      ESTABLISHED 9455/sshd: [accepte
tcp        0      0 165.22.43.156:80        179.126.139.213:65126   ESTABLISHED 9037/nginx: worker
tcp        0      0 165.22.43.156:80        179.126.139.213:6467    ESTABLISHED 9037/nginx: worker
tcp6       0      0 :::80                   :::*                    LISTEN      9029/nginx: master
tcp6       0      0 :::22                   :::*                    LISTEN      926/sshd

Do you know how I can fix it?

Bobby Iliev

Site Moderator

• September 26, 2020

Hi there @moisesalejandro,

What I could suggest in your case is to check your Docker container’s logs for more information on why the connections might be failing.

To do that, you can run the following: