nginx listens to two ports 80 and 81, but I can't find the configuration for 81! !

Inside nginx.conf

http{

<code>##
# Virtual Host Configs
##

include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;</code>

}

conf.d is empty. . .

sites-enabled

Then in the default file

server {

<code>listen 80 default_server;
listen [::]:80 default_server;
</code>

<code>root /data/www/;

# Add index.php to the list if you are using PHP
index index.html index.htm index.php;

server_name _;

location / {
    # First attempt to serve request as file, then
    # as directory, then fall back to displaying a 404.
    try_files $uri $uri/ =404;
}

# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
location ~ \.php$ {
    include snippets/fastcgi-php.conf;
#
#    # With php5-cgi alone:
    fastcgi_pass 127.0.0.1:9000;
#    # With php5-fpm:
#    fastcgi_pass unix:/var/run/php5-fpm.sock;
}

# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
#    deny all;
#}</code>

}
I didn’t even see the word 81