Cheat Sheets

Network - Black Hole Routes


Ensure that we do not forget about black hole routes. Those can be leftovers of DoS mitigation attempts and are easily forgotten producing issues for DSL customers.

Check Script:


ips=$(/sbin/route -n | grep "UGH.* lo$" | awk '{print $1}' | head -25) if [ "$ips" == "" ]; then result_ok else result_warning "Black hole routes found: $ips" fi
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