# Subdomain

## Whitelist an IP in NGINX for subdomain

Let’s say you have two subdomains (*blog.example.com* and *articles.example.com*) with their NGINX config files at */etc/nginx/sites-enabled/blog.conf* and */etc/nginx/sites-enabled/articles.conf*

If you want to whitelist an IP in NGINX for only 1 subdomain (e.g. blog.example.com), place the 2 lines below in the blog.conf file of that subdomain

```
sudo vim /etc/nginx/sites-enabled/blog.conf
```

```
server {
  server blog.example.com;
  allow 45.43.23.21;
  deny all;
}
```

If you want to whitelist an IP in both subdomains, then add the 2 lines in both *blog.conf* and *articles.conf* files.

## Restart NGINX

Run the following command to check the syntax of your updated config file.

```
sudo nginx -t
```

If there are no errors, run the following command to restart the NGINX server.

```
sudo systemctl restart nginx
```