This post is about running your ASP.NET Core application with Nginx as reverse proxy on Windows. Nginx is a web server. It can act as a reverse proxy server for HTTP, HTTPS, SMTP, POP3, and IMAP protocols, as well as a load balancer and an HTTP cache. Nginx runs on Unix, Linux, BSD variants, OS X, Solaris, AIX, HP-UX, and Windows. Released under the terms of a BSD-like license, Nginx is free and open source software. Few months back on K-MUG Techday, on a NodeJS session, I asked the question about using NodeJS in enterprise project, then I got introduced to Nginx and reverse proxy concepts in NodeJS. Similar to Node, ASP.NET Core is also supports the Kestrel hosting than IIS, it can be also used along with Nginx and can be hosted in Linux as well..

You can download the Windows version of Nginx from the Nginx download page. You can find more details on Nginx windows version here. Once downloaded, extract the Nginx zip file. And you can run the Nginx.exe file. By default Nginx.exe runs on port 80, if you have IIS installed and running, Nginx.exe will fail to start. You can configure the default port for nginx in the “nginx.conf” file, under “conf” directory. You can modify the server / listen property.

Here is the minimal Nginx configuration to use with Kestrel.

server {
    listen 8080;
    server_name 172.16.198.154;
    
    root /samplewebapp/wwwroot;

    location ~ \.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm|woff2|svg)$ {
        expires 1d;
        access_log off;
        add_header X-Static-File true;
    }

    location / {
        proxy_pass http://127.0.0.1:5000;
        proxy_set_header Connection "";
        proxy_http_version 1.1;
    }
}

You can configure Nginx for load balancing web applications as well. Right now I am configuring Nginx to load balance ASP.NET Core applications running on top of Kestrel. You can do it with Docker as well. For this post I am running Kestrel on different port numbers and load balancing using Nginx default load balancing strategy (Round Robin), and here is the configuraion for load balancing.

upstream localhostapp {
	server 172.16.198.154:5000;
	server 172.16.198.154:5001;
	server 172.16.198.154:5002;
}

server {
	listen       8080;
	server_name  172.16.198.154;

	location / {
		proxy_pass http://localhostapp;
		proxy_set_header Connection keep-alive;
		proxy_set_header Host $host;
	}
}

This configuration tells Nginx to accept requests on port 8080 and proxy those requests to 172.16.198.154:5000, 172.16.198.154:5001 and 172.16.198.154:5002. Now you can shutdown the Nginx.exe using “nginx -s quit” command and restart, and browse the application with 8080 port, you can see your application is load balanced.

Happy Programming :)