Nginx Block And Deny IP Address OR Network Subnets

How do I block or deny access based on the host name or IP address of the client visiting website under nginx web server?

Nginx comes with a simple module called ngx_http_access_module to allow or deny access to IP address. The syntax is as follows:

deny IP;
deny subnet;
allow IP;
allow subnet;
# block all ips
deny    all;
# allow all ips 
allow    all;

Note rules are checked in the order of their record to the first match.

How Do I Configure Nginx To Block IPs?

Edit nginx.conf file, enter (note my nginx path is set to /usr/local/nginx/, replace this according to your setup):
# cd /usr/local/nginx/conf/
# vi nginx.conf

Add the following line in http section:

## Block spammers and other unwanted visitors  ##
 include blockips.conf;

Save and close the file. Finally, create blockips.conf in /usr/local/nginx/conf/, enter:
# vi blockips.conf
Append / add entries as follows:

deny 1.2.3.4;
deny 91.212.45.0/24;
deny 91.212.65.0/24;

Save and close the file. Test the config file, enter:
# /usr/local/nginx/sbin/nginx -t
Sample outputs:

the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
configuration file /usr/local/nginx/conf/nginx.conf test is successful

Reload the new config, enter:
# /usr/local/nginx/sbin/nginx -s reload

How Do I Deny All and Allow Only Intranet/LAN IPs?

Edit config file as follows:

location / {
  # block one workstation
  deny    192.168.1.1;
  # allow anyone in 192.168.1.0/24
  allow   192.168.1.0/24;
  # drop rest of the world 
  deny    all;
}

Granted access to network 192.168.1.0/24 with the exception of the address 192.168.1.1.

How Do I Customize HTTP 403 Forbidden Error Messages?

Create a file called error403.html in default document root, enter:
# cd /usr/local/nginx/html
# vi error403.html

<html>
<head><title>Error 403 - IP Address Blocked</title></head>
<body>
Your IP Address is blocked. If you this an error, please contact webmaster with your IP at [email protected]
</body>
</html>

If SSI enabled, you can display the client IP easily from the html page itself:

Your IP Address is <!--#echo var="REMOTE_ADDR" --> blocked.

Save and close the file. Edit your nginx.conf file, enter:
# vi nginx.conf

# redirect server error pages to the static page
 error_page   403  /error403.html;
 location = /error403.html {
         root   html;
 }

Save and close the file. Reload nginx, enter:
# /usr/local/nginx/sbin/nginx -s reload

See also:

References:

Posted by: SXI ADMIN

The author is the creator of SXI LLC and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.