Access control using Fail2Ban and geoip

Geolookup

In order to do a geolookup from the command line, we have to get the GeoIP binary and database installed.

apt-get install geoip-bin geoip-database

Test it: geoiplookup 159.20.6.38 should give you GeoIP Country Edition: DK, Denmark

Fail2Ban

I assume Fail2ban is already installed and configured.

Create an action script: sudo vi /etc/fail2ban/action.d/geohostsdeny.conf

[Definition]

# Option:  actionstart
# Notes.:  command executed once at the start of Fail2Ban.
# Values:  CMD
#
actionstart = 

# Option:  actionstop
# Notes.:  command executed once at the end of Fail2Ban
# Values:  CMD
#
actionstop = 

# Option:  actioncheck
# Notes.:  command executed once before each actionban command
# Values:  CMD
#
actioncheck = 

# Option:  actionban
# Notes.:  command executed when banning an IP. Take care that the
#          command is executed with Fail2Ban user rights. 
#          Excludes PH|Philippines from banning.
# Tags:    See jail.conf(5) man page
# Values:  CMD
#
actionban = IP=<ip> &&
            COUNTRY=$(geoiplookup $IP | egrep "<country_list>") && [ "$COUNTRY" ] || 
            (printf %%b "<daemon_list>: $IP\n" >> <file>)

# Option:  actionunban
# Notes.:  command executed when unbanning an IP. Take care that the
#          command is executed with Fail2Ban user rights.
# Tags:    See jail.conf(5) man page
# Values:  CMD
#
actionunban = IP=<ip> && sed -i.old /ALL:\ $IP/d <file>

[Init]

# Option:  country_list
# Notes.:  List of exempted countries separated by pipe "|"
# Values:  STR  Default:  
#
country_list = DK|Denmark

# Option:  file
# Notes.:  hosts.deny file path.
# Values:  STR  Default:  /etc/hosts.deny
#
file = /etc/hosts.deny

# Option:  daemon_list
# Notes:   The list of services that this action will deny. See the man page
#          for hosts.deny/hosts_access. Default is all services.
# Values:  STR  Default: ALL
daemon_list = ALL

This script will ban all ip's except if it is located in a country that is mentioned in the 'country_list' line.

Enable it by editing sudo vi /etc/fail2ban/jail.local

Add banaction = geohostsdeny

Reference

• http://kbeezie.com/geoiplookup-command-line/
• https://www.webfoobar.com/node/54