Realtime Blacklist (RBLs), also called Realtime blacklists; are email blacklists primarily there to report any IP addresses and domains that are linked to spam.
To lookup your domain or IP address for blacklist monitoring, you can either go to individual blacklisting providers, or you can use comprehensive blacklist checking tools that checks multiple rbls for you:
- Reputable blacklisting providers:
- Barracuda Reputation Block List Lookup (BRBL)
- Invaluement Lookup
- SpamCop Lookup
- Spamhaus Lookup (One of the most reputable blacklists - ISPs are more likely to block more than 80% of your mail if you are listed at Spamhaus)
- Comprehensive blacklist checking tools: