Nginx and IP v6 - not best friends ...

Having installed Nginx on an Ubuntu 18.04.3 LTS box, I saw this: -

systemctl status nginx.service

● nginx.service - A high performance web server and a reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Mon 2019-09-30 02:04:20 PDT; 7s ago
     Docs: man:nginx(8)
  Process: 8643 ExecStop=/sbin/start-stop-daemon --quiet --stop --retry QUIT/5 --pidfile /run/nginx.pid (code=exited, status=0/SUCCESS)
  Process: 8477 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
  Process: 8644 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=1/FAILURE)
 Main PID: 8482 (code=exited, status=0/SUCCESS)

Sep 30 02:04:20 arnold.sideways.com systemd[1]: Starting A high performance web server and a reverse proxy server...
Sep 30 02:04:20 arnold.sideways.com nginx[8644]: nginx: [emerg] socket() [::]:80 failed (97: Address family not supported by protocol)
Sep 30 02:04:20 arnold.sideways.com nginx[8644]: nginx: configuration file /etc/nginx/nginx.conf test failed
Sep 30 02:04:20 arnold.sideways.com systemd[1]: nginx.service: Control process exited, code=exited status=1
Sep 30 02:04:20 arnold.sideways.com systemd[1]: nginx.service: Failed with result 'exit-code'.
Sep 30 02:04:20 arnold.sideways.com systemd[1]: Failed to start A high performance web server and a reverse proxy server.

As ever, Google helped: -

nginx erreur it didn't open

In essence, the problem was that Nginx was trying to bind to an IP version 6 ( IP v6 ) address, which wasn't available on this particular host.

This is controlled within the Nginx configuration file: -

/etc/nginx/sites-available/default

...

server {

        listen 80 default_server;

        listen [::]:80 default_server;

...

Once I removed ( commented out ) this line, and restarted Nginx: -

systemctl restart nginx.service

Nginx was A-OK: -

systemctl status nginx.service

● nginx.service - A high performance web server and a reverse proxy server

   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)

   Active: active (running) since Mon 2019-09-30 02:10:02 PDT; 5s ago

     Docs: man:nginx(8)

  Process: 8643 ExecStop=/sbin/start-stop-daemon --quiet --stop --retry QUIT/5 --pidfile /run/nginx.pid (code=exited, status=0/SUCCESS)

  Process: 9064 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=0/SUCCESS)

  Process: 9054 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)

 Main PID: 9068 (nginx)

    Tasks: 3 (limit: 2319)

   CGroup: /system.slice/nginx.service

           ├─9068 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;

           ├─9069 nginx: worker process

           └─9070 nginx: worker process

Sep 30 02:10:02 arnold.sideways.com systemd[1]: Starting A high performance web server and a reverse proxy server...

Sep 30 02:10:02 arnold.sideways.com systemd[1]: Started A high performance web server and a reverse proxy server.