www2.mkcs.at

This host detects connection attempts to several unusual ports, like TCP 23/telnet. Then the host gets blacklisted and its IP address gets published in order to warn others.

Feel free to download the list of hosts (file 1) which can be used for the ipset command.
Feel free to download the list of hosts (file 2) which can be used for the ipset command.
Feel free to download the list of hosts (file 3) which can be used for the ipset command.
Feel free to download the list of hosts (file 4) which can be used for the ipset command.
Feel free to download the list of hosts (file 5) which can be used for the ipset command.

Example:

ipset -N blocked iphash
iptables -t filter -A INPUT -m set --match-set blocked src -j DROP
grep -v "create" blocked_hosts.txt | ipset restore

If you feel your host got blocked in error, feel free to write an email to mkspamx-common@yahoo.de.