Email Blacklist Check
Resolve a domain's MX hosts to IPs and check each against 49 IP blacklists plus the domain against 9 domain blacklists.
Monitor this automatically
NetTests can run this check on a schedule, preserve historical results, compare changes over time, and alert you the moment something breaks.
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What is an email blacklist (DNSBL)?
A DNSBL (DNS-based Blackhole List) is a list of IP addresses or domains known to send spam or abuse. Receiving mail servers query these lists in real time during the SMTP connection. Being listed on Spamhaus SBL causes immediate delivery failures with most major mail providers.
Why does this tool check MX host IPs rather than my domain IP?
IP blacklists target the IPs that actually send email — your MX servers. This tool resolves your domain's MX records to their IP addresses and checks each against IP-based RBLs (Spamhaus, SORBS, Barracuda, SpamCop, etc.). It also checks the domain itself against domain blacklists (DBL) that block known malicious domains regardless of IP.
I'm listed — how do I get delisted?
First fix the root cause: malware, open relay, or compromised account. Then visit the blacklist's delisting page. Spamhaus SBL/XBL, SORBS, and SpamCop offer self-service removal; Barracuda requires a form. Spamhaus PBL listings are by policy for residential IPs — use your ISP's relay or a business mail service rather than direct sending.
How often should I check for blacklistings?
After any mail infrastructure change, or whenever you notice a deliverability drop. For production servers, automated daily checks are recommended — listing status can change within hours of a spam incident without any direct notification to you.