BOGON Address List

You can use this Bogon list with your firewall config, replacing the illegal-addr address lists from the Dmitry on firewalling rules.

/ip firewall address-list
add list=BOGONS address=192.168.0.0/16
add list=BOGONS address=10.0.0.0/8
add list=BOGONS address=172.16.0.0/12
add list=BOGONS address=169.254.0.0/16
add list=BOGONS address=127.0.0.0/8
add list=BOGONS address=224.0.0.0/3 comment="multicast - 224.0.0.0/3"
add list=BOGONS address=223.0.0.0/8
add list=BOGONS address=198.18.0.0/15
add list=BOGONS address=192.0.2.0/24
add list=BOGONS address=185.0.0.0/8
add list=BOGONS address=180.0.0.0/6
add list=BOGONS address=179.0.0.0/8
add list=BOGONS address=176.0.0.0/7
add list=BOGONS address=175.0.0.0/8
add list=BOGONS address=104.0.0.0/6
add list=BOGONS address=100.0.0.0/6
add list=BOGONS address=49.0.0.0/8
add list=BOGONS address=46.0.0.0/8
add list=BOGONS address=42.0.0.0/8
add list=BOGONS address=39.0.0.0/8
add list=BOGONS address=36.0.0.0/7
add list=BOGONS address=31.0.0.0/8
add list=BOGONS address=27.0.0.0/8
add list=BOGONS address=23.0.0.0/8
add list=BOGONS address=14.0.0.0/8
add list=BOGONS address=5.0.0.0/8
add list=BOGONS address=2.0.0.0/8
add list=BOGONS address=0.0.0.0/7
add list=BOGONS address=128.0.0.0/16

Wikipedia links on Bogons and Multicast