Editing NGINX Basic Authentication (section)

=== Combining Basic Authentication with Access Restriction by IP Address ===
HTTP basic authentication can be effectively combined with access restriction by IP address. You can implement at least two scenarios:

* a user must be both authenticated and have a valid IP address
* a user must be either authenticated, or have a valid IP address
* Allow or deny access from particular IP addresses with the allow and deny directives:

 location /api {
     #...
     deny  192.168.1.2;
     allow 192.168.1.1/24;
     allow 127.0.0.1;
     deny  all;
 }
Access will be granted only for the 192.168.1.1/24 network excluding the 192.168.1.2 address. Note that the allow and deny directives will be applied in the order they are defined.

Combine restriction by IP and HTTP authentication with the satisfy directive. If you set the directive to to all, access is granted if a client satisfies both conditions. If you set the directive to any, access is granted if if a client satisfies at least one condition:
 location /api {
     #...
     satisfy all;    
     deny  192.168.1.2;
     allow 192.168.1.1/24;
     allow 127.0.0.1;
     deny  all;
     auth_basic           "Administrator’s Area";
     auth_basic_user_file conf/htpasswd;
 }