• sudo lsof -i :80
  • stop the application use port 80

    • COMMAND     PID     USER   FD   TYPE   DEVICE SIZE/OFF NODE NAME
      apache2    1371     root    4u  IPv6    35827      0t0  TCP *:http (LISTEN)
      kited      3329   shumin   13u  IPv4 28432404      0t0  TCP PC.private.network:38926->tsa01s11-in-f14.1e100.net:http (ESTABLISHED)
      apache2 2281767 www-data    4u  IPv6    35827      0t0  TCP *:http (LISTEN)
      apache2 2281768 www-data    4u  IPv6    35827      0t0  TCP *:http (LISTEN)

    • check who use apache2

    • (base) shumin@PC:~$ ls /etc/apache2/sites-enabled/
      000-default.conf
      (base) shumin@PC:~$ cat /etc/apache2/sites-enabled/000-default.conf 
      <VirtualHost *:80>
      	# The ServerName directive sets the request scheme, hostname and port that
      	# the server uses to identify itself. This is used when creating
      	# redirection URLs. In the context of virtual hosts, the ServerName
      	# specifies what hostname must appear in the request's Host: header to
      	# match this virtual host. For the default virtual host (this file) this
      	# value is not decisive as it is used as a last resort host regardless.
      	# However, you must set it for any further virtual host explicitly.
      	#ServerName www.example.com
      
      	ServerAdmin webmaster@localhost
      	DocumentRoot /var/www/html
      
      	# Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
      	# error, crit, alert, emerg.
      	# It is also possible to configure the loglevel for particular
      	# modules, e.g.
      	#LogLevel info ssl:warn
      
      	ErrorLog ${APACHE_LOG_DIR}/error.log
      	CustomLog ${APACHE_LOG_DIR}/access.log combined
      
      	# For most configuration files from conf-available/, which are
      	# enabled or disabled at a global level, it is possible to
      	# include a line for only one particular virtual host. For example the
      	# following line enables the CGI configuration for this host only
      	# after it has been globally disabled with "a2disconf".
      	#Include conf-available/serve-cgi-bin.conf
      </VirtualHost>
      
      # vim: syntax=apache ts=4 sw=4 sts=4 sr noet
      
      (base) shumin@PC:~$ ls -l /var/www/html/
      總用量 12
      -rw-r--r-- 1 root root 10918 10月  7  2020 index.html

    • index.html is a default apache page, so no application use apache2
    • sudo systemctl stop apache2
    • check port 80 again

    • (base) shumin@PC:~$ sudo lsof -i :80
      COMMAND  PID   USER   FD   TYPE   DEVICE SIZE/OFF NODE NAME
      kited   3329 shumin   13u  IPv4 28432404      0t0  TCP PC.private.network:38926->tsa01s11-in-f14.1e100.net:http (ESTABLISHED)
      

    • sudo venv/bin/python3 project_dir/manage.py runserver 0.0.0.0:80
      • run without error 

ALLOWED_HOSTS = ['*']