Linux · 2012-02-08

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:
Nginx Shell Script To Block Spamhaus Lasso Drop Spam IP Address