nginx：有没有办法避免在 nginx 配置文件中写入服务器 ip 地址？

Question

I used nginx as a reverse proxy in a simple express app. In my config file, I have used server ip( http://45.33.97.232/ ) as server_name.

but is there any way to avoid writing the actual server ip in this file without breaking anything?

server {
    listen 80 default_server;
    server_name 45.33.97.232;

location / {
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $remote_addr;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_pass http://45.33.97.232:3000; #port where you are serving your express app.

  }
}

Answer 1

Yes. By setting the default_server flag in the listen directive and setting the server name to any invalid domain name. Typically the name _ is used in nginx example config files but this can be any invalid domain name such as ! etc:

server {
    listen 80 default_server;
    server_name _;

    ...
}

See http://nginx.org/en/docs/http/server_names.html#miscellaneous_names for more info on this.

---

Note that there is one special server name that has an additional meaning. If you need to serve clients that don't send the Host header (eg. HTTP/1.0 clients) then the empty string is used to signal that this server block is the one that is meant to serve such clients. So the server_name can be set to two double quotes ( "" ) to signify empty string:

server {
    listen 80;
    server_name "";

    ...
}

Note though that this does not function as a catch-all domain name like the _ above. Instead it catches requests with empty host header.