🚫 Email & IP Blacklist Checker
Check if your domain or IP address is listed on 30+ email blacklists (DNSBLs). Being blacklisted can severely impact email deliverability.
What are Email Blacklists?
Email blacklists (also called DNSBLs or RBLs) are databases of IP addresses and domains known to send spam or malicious email. Mail servers use these lists to filter incoming email.
Why Does Being Blacklisted Matter?
- Emails get rejected: Many mail servers will outright reject email from blacklisted senders
- Emails go to spam: Even if delivered, blacklisted senders often end up in spam folders
- Reputation damage: Being blacklisted indicates security issues or spam complaints
Common Reasons for Blacklisting
- Sending spam (intentionally or from a compromised server)
- Open relay or misconfigured mail server
- Malware infection sending spam
- Shared IP with a spammer (common on shared hosting)
- High complaint rates from recipients
- Poor list hygiene (sending to invalid addresses)
How to Get Delisted
- Identify the cause: Check your server logs and security
- Fix the issue: Remove malware, fix configurations, clean your list
- Request removal: Each blacklist has its own delisting process
- Monitor: Keep checking to ensure you don't get relisted
How a Blacklist Check Works
DNS blacklists are queried through ordinary DNS. To check the IP 192.0.2.1 against Spamhaus ZEN, the checker reverses the IP's octets and looks up 1.2.0.192.zen.spamhaus.org:
- No answer (NXDOMAIN): the IP isn't listed.
- An answer in
127.0.0.x: the IP is listed. The last number is the reason code, such as127.0.0.2for the Spamhaus SBL or127.0.0.4for the exploits list (XBL). - An error code: the list refused the query. Spamhaus answers
127.255.255.254to lookups from public or shared resolvers, and URIBL and SURBL answer127.0.0.1. These aren't listings, so DNSLens shows them as "couldn't check".
Domain blacklists such as the Spamhaus DBL and SURBL work the same way, with the domain name in place of the reversed IP. Spamhaus's 127.0.0.10 and 127.0.0.11 answers come from its Policy Block List (PBL), which lists IP ranges that shouldn't send email directly, like home broadband. That's normal for a web server.
Frequently Asked Questions
How do I check if my IP or domain is blacklisted?
Enter the IP address or domain above. The checker queries 30+ DNS-based blacklists (DNSBLs) at once and shows which, if any, list you, with the reason code where the list provides one. For a domain, it checks both the domain blacklists and the IP the domain resolves to.
Why does a list say "couldn't check"?
Some blocklists, including Spamhaus, refuse lookups that come through shared cloud DNS resolvers and answer with an error code instead of a result. That's not a listing. Use the "Check directly" link to look the IP up on that list's own site.
Can I monitor blacklists continuously?
This is a one-off check; DNSLens doesn't send alerts. Re-run it after any jump in bounces or spam-folder complaints, and after changes to your sending setup. DMARC aggregate reports are a good early warning too: read them with the DMARC Report Analyzer.
Why is my domain blacklisted if I don't send spam?
Common causes: a shared IP used by another sender, a compromised mailbox or web form sending spam, or mailing old, unverified lists that hit spam traps.
How long does delisting take?
It varies by list. Some remove an entry automatically once the spam stops; others need a removal request after you've fixed the cause. Fix the cause first, then request removal, or you'll be relisted.