fail2ban/config/action.d/route.conf

# Fail2Ban configuration file
#
# Author: Michael Gebetsroither
#
# This is for blocking whole hosts through blackhole routes.
#
# PRO:
#   - Works on all kernel versions and as no compatibility problems (back to debian lenny and WAY further).
#   - It's FAST for very large numbers of blocked ips.
#   - It's FAST because it Blocks traffic before it enters common iptables chains used for filtering.
#   - It's per host, ideal as action against ssh password bruteforcing to block further attack attempts.
#   - No additional software required beside iproute/iproute2
#
# CON:
#   - Blocking is per IP and NOT per service, but ideal as action against ssh password bruteforcing hosts

[Definition]
actionban   = ip route add <blocktype> <ip>
actionunban = ip route del <blocktype> <ip>

# Option:  blocktype
# Note:    Type can be blackhole, unreachable and prohibit. Unreachable and prohibit correspond to the ICMP reject messages.
# Values:  STRING
blocktype = unreachable