iptables geoip xtables firewall by country

geoip.sh

# This is an example of how to use xtables / xt_geoip to block requests
# based on their source/destination country. 
#
# It can be computationally expensive to have tons of iptables rules. 
# According to the bottom of the following page, this xt_geoip is probably 
# about as efficient as can be for doing this kind of thing:
# http://xtables-addons.sourceforge.net/geoip.php

# Install packages
apt-get install xtables-addons-common libtext-csv-xs-perl unzip

# Create the directory where the country data should live
mkdir /usr/share/xt_geoip

# Download and install the latest country data
mkdir /tmp/xt_geoip_dl
cd /tmp/xt_geoip_dl
/usr/lib/xtables-addons/xt_geoip_dl
/usr/lib/xtables-addons/xt_geoip_build -D /usr/share/xt_geoip *.csv

# Test it out. Singapore should get blocked, but anywhere else should get 
# through. Test it on your VPS provider by firing up a couple machines in 
# different countries.
iptables -I INPUT 1 -m geoip --src-cc SG -j DROP

This failed on Linode. They don't include the kernel module, so we'd have to download the linux source, then compile and load the module.

Thanks for this, it was helpful. The xtables-addons directory was in /usr/libexec for me(Oracle Ubuntu 20.04), so those lines would be:
/usr/libexec/xtables-addons/xt_geoip_dl
/usr/libexec/xtables-addons/xt_geoip_build -D /usr/share/xt_geoip *.csv