A large ISP gave me their inbound BGP prefix-list used to block customers from advertising invalid addresses:
ip prefix-list Denylist description Denied Internet prefixes
ip prefix-list Denylist seq 10 deny 0.0.0.0/0
ip prefix-list Denylist seq 20 deny 192.42.172.0/24 le 32
ip prefix-list Denylist seq 200 deny 0.0.0.0/8 le 32
ip prefix-list Denylist seq 201 deny 1.0.0.0/8 le 32
ip prefix-list Denylist seq 202 deny 2.0.0.0/8 le 32
ip prefix-list Denylist seq 203 deny 5.0.0.0/8 le 32
ip prefix-list Denylist seq 204 deny 7.0.0.0/8 le 32
ip prefix-list Denylist seq 205 deny 23.0.0.0/8 le 32
ip prefix-list Denylist seq 206 deny 27.0.0.0/8 le 32
ip prefix-list Denylist seq 207 deny 31.0.0.0/8 le 32
ip prefix-list Denylist seq 208 deny 36.0.0.0/8 le 32
ip prefix-list Denylist seq 209 deny 37.0.0.0/8 le 32
ip prefix-list Denylist seq 210 deny 39.0.0.0/8 le 32
ip prefix-list Denylist seq 211 deny 42.0.0.0/8 le 32
ip prefix-list Denylist seq 212 deny 49.0.0.0/8 le 32
ip prefix-list Denylist seq 213 deny 50.0.0.0/8 le 32
ip prefix-list Denylist seq 214 deny 92.0.0.0/8 le 32
ip prefix-list Denylist seq 215 deny 93.0.0.0/8 le 32
ip prefix-list Denylist seq 216 deny 94.0.0.0/8 le 32
ip prefix-list Denylist seq 217 deny 95.0.0.0/8 le 32
ip prefix-list Denylist seq 218 deny 100.0.0.0/8 le 32
ip prefix-list Denylist seq 219 deny 101.0.0.0/8 le 32
ip prefix-list Denylist seq 220 deny 102.0.0.0/8 le 32
ip prefix-list Denylist seq 221 deny 103.0.0.0/8 le 32
ip prefix-list Denylist seq 222 deny 104.0.0.0/8 le 32
ip prefix-list Denylist seq 223 deny 105.0.0.0/8 le 32
ip prefix-list Denylist seq 224 deny 106.0.0.0/8 le 32
ip prefix-list Denylist seq 225 deny 107.0.0.0/8 le 32
ip prefix-list Denylist seq 226 deny 108.0.0.0/8 le 32
ip prefix-list Denylist seq 227 deny 109.0.0.0/8 le 32
ip prefix-list Denylist seq 228 deny 110.0.0.0/8 le 32
ip prefix-list Denylist seq 229 deny 111.0.0.0/8 le 32
ip prefix-list Denylist seq 230 deny 112.0.0.0/8 le 32
ip prefix-list Denylist seq 231 deny 113.0.0.0/8 le 32
ip prefix-list Denylist seq 232 deny 114.0.0.0/8 le 32
ip prefix-list Denylist seq 233 deny 115.0.0.0/8 le 32
ip prefix-list Denylist seq 234 deny 127.0.0.0/8 le 32
ip prefix-list Denylist seq 235 deny 169.254.0.0/16 le 32
ip prefix-list Denylist seq 236 deny 172.16.0.0/12 le 32
ip prefix-list Denylist seq 237 deny 173.0.0.0/8 le 32
ip prefix-list Denylist seq 238 deny 174.0.0.0/8 le 32
ip prefix-list Denylist seq 239 deny 175.0.0.0/8 le 32
ip prefix-list Denylist seq 240 deny 176.0.0.0/8 le 32
ip prefix-list Denylist seq 241 deny 177.0.0.0/8 le 32
ip prefix-list Denylist seq 242 deny 178.0.0.0/8 le 32
ip prefix-list Denylist seq 243 deny 179.0.0.0/8 le 32
ip prefix-list Denylist seq 244 deny 180.0.0.0/8 le 32
ip prefix-list Denylist seq 245 deny 181.0.0.0/8 le 32
ip prefix-list Denylist seq 246 deny 182.0.0.0/8 le 32
ip prefix-list Denylist seq 247 deny 183.0.0.0/8 le 32
ip prefix-list Denylist seq 248 deny 184.0.0.0/8 le 32
ip prefix-list Denylist seq 249 deny 185.0.0.0/8 le 32
ip prefix-list Denylist seq 250 deny 186.0.0.0/8 le 32
ip prefix-list Denylist seq 251 deny 187.0.0.0/8 le 32
ip prefix-list Denylist seq 252 deny 192.0.2.0/24 le 32
ip prefix-list Denylist seq 253 deny 192.168.0.0/16 le 32
ip prefix-list Denylist seq 254 deny 197.0.0.0/8 le 32
ip prefix-list Denylist seq 255 deny 198.18.0.0/15 le 32
ip prefix-list Denylist seq 256 deny 223.0.0.0/8 le 32
ip prefix-list Denylist seq 257 deny 224.0.0.0/3 le 32
