Mail Blacklist Check
Check whether an IP address, hostname, domain or email is listed on public DNS blacklists (RBLs). For hostnames/domains/emails the tool resolves them to IP(s) via DNS (A, AAAA, and for domains the first MX host), then checks those IPs.
Why check email blacklists?
If your mail server or IP is on an RBL (Realtime Blacklist), many receivers will reject or spam-filter your messages. This blacklist checker looks up your IP (or hostname, domain, or email) against common public RBLs so you can delist or fix issues.
How RBLs work
RBLs are DNS-based lists: the receiver looks up a reversed IP (e.g. 1.2.3.4 becomes 4.3.2.1.list.example.com). If the lookup returns a result, the IP is listed. Lists are maintained by various organisations and may list IPs that sent spam, have open relays, or are in hijacked ranges. Each list has its own policy and delisting process; you must follow the list’s website to request removal. Fixing the cause (e.g. stopping spam, closing an open relay) is usually required before delisting.
Quick tips
- Check all IPs you send from; shared hosting or a single bad IP can list the whole range.
- Each list has its own delisting process; follow the link or instructions on the list’s site.
- Fix the cause (spam, open relay, compromised server) before requesting removal, or you may be re-listed.
Things to consider
Not all receivers use the same lists; being off one RBL does not guarantee delivery. Some lists are strict; others are rarely used. Keep sending practices clean to avoid listing.
ve.ms — Free tools for a more reliable internet. Last updated 2026.