RISK LEVELS
| LOW | Not listed on any blacklist |
| MEDIUM | Listed on 1-2 blacklists |
| HIGH | Listed on 3-4 blacklists |
| CRITICAL | Listed on 5+ blacklists |
Blacklist Checker
Check if an IP address or domain is listed on DNS blacklists
MAJOR BLACKLISTS
| Spamhaus | Industry standard, multiple lists |
| Barracuda | Enterprise spam filtering |
| SpamCop | User-reported spam sources |
| SORBS | Open relay and spam sources |