DNS Black List
Email Blacklist Check - See if your server is blacklisted. Open Relay Test. SORBS (Spam and Open-Relay Blocking System) Spam Links - dead dnsbls and rhsbls. Skip over navigation The DNSBLs on this page are either confirmed dead or presumed dead - you should no longer be using them.
Check the list of DNSBLs you have carefully against this list. Njabl.org. The CBL. SpamCop.net - Beware of cheap imitations. The Spamhaus Project.