IP Blacklist Checker – check an IP against blacklists
The IP Blacklist Check lets you check an IPv4 address or your mail server's hostname against 11 spam blacklists (RBL/DNSBL), including Spamhaus, Barracuda and SpamCop. For each list, you'll see whether the IP is listed, not listed or could not be checked, along with its reverse DNS record (PTR). For matches, you'll see the type of listing and, for most lists, a removal link.
Built by Luca Stanek
Free and with no sign-up: enter an IP address or hostname and see which blacklists list it in seconds.
Running your own mail server? Get a dedicated IP you control.
Enter your mail server’s IP address. For a hostname, we check its first public IPv4 address.
Example result
What the result looks like in the IP Blacklist Checker
You enter an IPv4 address or your mail server's hostname, and the checker queries all lists simultaneously and shows a summary, the reverse DNS record, and the reason and delisting link for each match. The IP, hostname, and matches below are fictional.
Example · Example with fictional data for 192.0.2.25
Listed on 1 of 11 lists- Listed
- 1
- Matches counted against the IP. A Spamhaus PBL listing does not count; it is only informational.
- Not listed
- 9
- Lists that confirmed they have no entry for the IP.
- Cannot be checked
- 0
- Lists that did not respond or refused the query. They never count as clean.
Result for each blacklist
- 1 error
- 1 note
Note · Spamhaus ZEN · 127.0.0.10Dynamic address range: email should be sent through a relay. This is not a penalty against this IP.
Review entry & request removal: https://check.spamhaus.org/
Error · SpamCop · 127.0.0.2Listed as a spam source.
Review entry & request removal: https://www.spamcop.net/bl.shtml
OKReverse DNS (PTR): mail.example.com
If the PTR record is missing, many mail servers reject emails from the IP.
OKNot listed on 9 lists: Barracuda Reputation Block List, Passive Spam Block List (PSBL), UCEPROTECT Level 1, UCEPROTECT Level 2, UCEPROTECT Level 3, DroneBL, InterServer RBL, GBUdb Truncate, s5h.net
How it works
How to check your IP against blacklists and request removal
From the first blacklist check to delisting: what to do when your emails aren't arriving.
Step 1
Enter IP or hostname
Enter your mail server's IPv4 address (e.g. 203.0.113.10) or hostname (e.g. mail.example.com) in the input field. You don't need an account.
Step 2
Start check
Click “Check”. The checker queries all 11 blacklists at once and retrieves the reverse DNS record. It first resolves a hostname to its first public IPv4 address.
Step 3
Read summary
At the top, you'll see how many lists include the IP, counts for listed, not listed and could not be checked, and the PTR record.
Step 4
Check results for each blacklist
Each list appears with its status. For a match, the checker shows the listing type—such as spam source, compromised host, network range, or PBL notice—and the list's response code.
Step 5
Fix the cause and request removal
Check your mail logs, change passwords, remove malware and close open relays. Then request removal from the list operator: For most lists, the “Check entry & request removal” link takes you straight to the operator's page.
Step 6
Check again
Check the IP again after a few hours until no list reports it as listed. The checked address will then appear in the URL, so you can share the link with your provider or team.
Analysis
Understanding blacklist results: What the statuses mean
Not every listing is equally serious. Here's how the checker classifies matches, notices, and lists it couldn't check.
Listed as a spam source
The list identifies the IP as a spam sender. This counts as a match for the IP and is the first thing to investigate if you're having delivery issues.
Infected or compromised host
Spamhaus ZEN (XBL section) and DroneBL list IPs identified as infected or abusive hosts. Check the server for malware before requesting removal.
Network range listed: UCEPROTECT Levels 2 and 3
Level 1 lists individual IPs; Levels 2 and 3 list entire network ranges or providers. The checker counts these as matches but notes that your IP is not necessarily the cause. Many mail servers disregard these levels, so focus on Spamhaus, Barracuda and Level 1 first.
Spamhaus PBL: advisory only
Spamhaus ZEN codes 127.0.0.10 and 127.0.0.11 indicate the Policy Block List for dynamic IP ranges. The checker shows them as notices, not blacklist matches.
Unreachable or query refused
If a list doesn't respond in time or rejects the query, it appears as unable to be checked, never as clear. The summary then notes that an all-clear result cannot be confirmed.
Reverse DNS (PTR)
Alongside the lists, the checker shows the IP's PTR record. If it's missing, many mail servers reject email from the IP even when it isn't blacklisted.
What the IP Blacklist Checker is useful for
Blacklist Check for mail servers: troubleshoot delivery issues
If emails aren't arriving, a blacklist check is a quick first step: results in seconds, with removal links for most lists.
Emails aren't arriving
Are recipients rejecting your emails, or are they landing in spam? A blacklist entry is one of the most common causes, and you can check for it in seconds.
Set up a new mail server
Used IP addresses sometimes have a history. Check the IP before sending your first newsletter or invoices through it.
After a hack or spam incident
After a mailbox or script is compromised, you can see which lists your IP has ended up on and what type of listing it has.
Check regularly
An IP can be added to a list at any time. Check again before campaigns and after changes to your mail setup.
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FAQ
Frequently asked questions about the IP Blacklist Check
Quick answers about blacklists, removal and this checker.
A DNS blacklist is a public list of IP addresses associated with spam or attacks. Receiving mail servers check these lists via DNS and reject mail from listed IPs or mark it as spam. Each list has its own rules, so an IP can appear on one list but not on others.
Enter your mail server's IPv4 address or hostname above and click “Check”. The checker queries 11 lists at once: Spamhaus ZEN, Barracuda Reputation Block List, SpamCop, Passive Spam Block List (PSBL), UCEPROTECT Level 1, UCEPROTECT Level 2, UCEPROTECT Level 3, DroneBL, InterServer RBL, GBUdb Truncate, s5h.net. For each list, you'll see “Listed”, “Not listed”, “Unreachable”, or “Query rejected”, along with a summary and the IP's reverse DNS record.
Common causes include a hacked mailbox or script sending spam, an open relay, bulk email sent without consent, or the IP's previous owner's history. On shared servers, another customer on the same network may also be responsible. Identify the cause first, or the IP will be listed again shortly after removal.
First fix the cause (change passwords, remove malware, close the open relay), then request delisting from the list operator. For most lists, a match includes a link to the provider's lookup and delisting page. How long it takes depends on the list: some remove the IP immediately after a request, others after hours or days, and many delist it automatically after a few days without new incidents. DNS caches may briefly delay the change, and the checker caches a result for no more than two minutes.
Neither is an all-clear: the checker counts these lists as unable to be checked, never as clear. “Unreachable” means the list didn't respond in time. “Query rejected” means the list doesn't answer queries from our server. This mainly affects Spamhaus, which blocks public resolvers and high query volumes. Check the IP directly with the provider in that case. The checker does not cache results containing lists it couldn't check.
The Spamhaus Policy Block List (PBL) contains address ranges that should not send email directly, such as residential and dynamic connections. This is not a penalty against your IP; it means you should send email through a relay server (smarthost). The checker therefore marks PBL as a notice and does not count it as a blacklist hit.
The lists checked contain IP addresses of sending mail servers, not individual email addresses. If you enter a hostname such as mail.example.com, the checker resolves it to its first public IPv4 address and checks that IP. It does not query domain-based lists. IPv6 is not supported because most blacklists do not offer IPv6 lookups, and the checker rejects private and loopback addresses.
A blacklist is only one possible cause. Another common issue is a missing reverse DNS record (PTR): many mail servers reject email from IPs without a PTR record. The checker shows the PTR record directly in the result. Your domain's SPF, DKIM, and DMARC should also be correct; you can check them with the Email DNS Health Checker.
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