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DNS Blacklist (RBL) Check

Query 22 public DNS-based blocklists to see whether your sending IP or domain is listed. Mail receivers use these lists to filter spam and phishing; being on one is a leading cause of "my email keeps going to spam." We query all of them in parallel so the check finishes in seconds.

IPs are checked against 18 IP-style RBLs (Spamhaus Zen, SpamCop, Barracuda, and more). Domains are checked against 4 URI-style RBLs (Spamhaus DBL, SURBL, and more). IPv6 not supported (most public RBLs are IPv4-only).

What is an RBL?

A Realtime Blackhole List (also called a DNSBL or DNS blocklist) is a published list of IPs or domains believed to send spam, phishing, or other unwanted mail. Mail servers query these lists during inbound mail delivery and can reject or quarantine matched messages.

Being listed doesn't mean you're a bad actor. Common causes: a shared mail server got compromised; a forwarder you used got abused; a former owner of your IP address sent spam. The fastest path to delisting is usually direct contact with the operator of each list (links in their respective sites).

Frequently asked questions

What is a DNS blacklist (DNSBL / RBL)?▾

A DNS blacklist, also called a DNSBL or RBL (Realtime Blackhole List), is a published list of IPs or domains believed to send spam or phishing. Receiving mail servers query these lists during delivery and can reject or quarantine matched messages, so a listing hurts your deliverability.

Why is my domain or IP on a blacklist?▾

A listing does not always mean you are a bad actor. Common causes are a shared mail server that got compromised, a forwarder you used being abused, or a previous owner of your IP address having sent spam. Check the specific list to see why it flagged you.

How do I get delisted from a blacklist?▾

Fix the underlying cause first (secure the account, stop the abusive sender, tighten SPF/DKIM/DMARC), then request removal directly with the operator of each list that has you listed. Delisting before you fix the cause usually results in a re-listing.

Does being on a blacklist affect SPF, DKIM, or DMARC?▾

They are separate systems. A blacklist listing affects reputation-based filtering, while SPF, DKIM, and DMARC affect authentication. A domain can pass all three and still be blacklisted, so it is worth checking both.