nginx不提供对外部IP地址的请求

我在端口81上运行nginx.我可以使用telnet 127.0.0.1进行telnet,一切都很好.

但是当我尝试从我的Mac(外部IP地址)telnet到我的机器时,我只是得到这个错误：

telnet: connect to address 109.123.x.x: Connection refused
telnet: Unable to connect to remote host

这是我的/ etc / nginx / sites-available / default文件：

server {
        listen   81; ## listen for ipv4; this line is default and implied
        #listen   [::]:80 default ipv6only=on; ## listen for ipv6

        root /usr/share/nginx/www;
        index index.html index.htm;

        # Make site accessible from http://localhost/
        server_name 109.123.x.x;

        location / {
                # First attempt to serve request as file,then
                # as directory,then fall back to index.html
                try_files $uri $uri/ /index.html;
        }
        ...

我打开了Ubuntu防火墙(ufw)以允许端口81.

我现在完全被困住了.

有人有主意吗？