IP blacklist check
Find out whether an IP address is on a public spam blocklist. If your emails are bouncing or landing in spam, check the IP address your mail server sends from.
20 free lookups a day, no account needed. IPv4 addresses only: spam blocklists don’t list IPv6 addresses one by one.
Listed on 1 of 4 blocklists
- bl.spamcop.net
- Listed 127.0.0.2
- psbl.surriel.com
- Not listed
- dnsbl-1.uceprotect.net
- Not listed
- all.s5h.net
- Not listed
Example result.
What a blacklist check tells you
Mail servers ask DNS-based blocklists (DNSBLs) about every connecting IP address and reject or junk mail from listed ones.
- Whether you’re listed
- A yes or no for each blocklist we query, with the return code that some lists use to say why.
- Where the problem is
- Each list has its own removal process. Knowing which one listed you tells you where to go to request delisting.
- Whether to trust a sender
- Run it the other way round too: an IP listed on several blocklists is a strong signal of spam or a compromised machine.
Need more than 20 a day?
Check sign-up and login IPs, or monitor your own mail servers. On the TrustLookup API a blacklist check uses no credits on any plan, and you can combine it with IP intelligence (1 credit) for location, ASN, proxy and Tor flags.
Request
curl https://api.trustlookup.io/v1/lookup \
-H "Authorization: Bearer $TRUSTLOOKUP_KEY" \
-d q="203.0.113.45" \
-d checks="ip,ip_blacklist"Response (shortened)
{
"type": "ipv4",
"results": {
"ip_blacklist": {
"ok": true,
"credits": 0,
"data": {
"ip": "203.0.113.45",
"listed": true,
"lists": [
{ "zone": "bl.spamcop.net", "listed": true, "return_code": "127.0.0.2" },
{ "zone": "psbl.surriel.com", "listed": false, "return_code": null }
]
}
}
}
}Questions
Is this blacklist check free?
Yes. This page checks up to 20 addresses a day without an account. On the API, blacklist checks use no credits.
Which blocklists do you check?
SpamCop, PSBL, UCEPROTECT level 1 and s5h.net. We don’t query Spamhaus: its terms require a paid licence for commercial use, so check Spamhaus on its own site.
My IP is listed. How do I get it removed?
First fix the cause: a compromised account, an open relay, or a sudden burst of mail to old addresses. Then follow the listed blocklist’s removal steps on its website. SpamCop and PSBL listings also expire on their own once the spam stops.
Can I check my email domain instead of an IP?
Blocklists like these list IP addresses, so check the IP your mail server sends from. You can find it in the “Received” headers of an email you sent. To check your domain’s SPF and DMARC records, use the email DNS check in the API.
Why does a list show “No answer”?
Blocklists are run by volunteers and small teams, and they sometimes rate-limit or time out. A “No answer” means we couldn’t tell either way, not that you’re listed.
Run these checks from your app
250 free credits every month for phone, email, IP and domain checks. NPI, USDOT and blacklist checks don’t use credits.