What is SPFBL?
Still have a question, spotted an error, or have a better explanation or a source we should cite?
dnsbl.spfbl.net checks IPs and domains. SPFBL.net runs it.
What the operator says
"complaints are made by their own recipients" SPFBL, DNSBL, read 31 Oct 2026.
What it really measures
Reputation from recipients' complaints across its customers. The number the lookup returns says which case you are:
| Number | Meaning |
|---|---|
| 127.0.0.2 | Bad reputation, confirmed by complaints |
| 127.0.0.3 | Hard to identify who is responsible, or the server breaks the mail standard |
| 127.0.0.4 | No mail service found, a NAT router, or a home connection |
| 127.0.0.5 | The abuse team for that range is not acting on reports |
What to think about
The operator says this list must not be used to reject mail, only to send it to Junk. If the IP has no mail server on it, it says not to worry.
How to get off it
Use the delist page, for mail administrators only. The free route needs reverse DNS matching your own domain (a paid-for domain with public ownership details), a working postmaster address, and negative points under 25 percent of send volume. If you cannot meet those, a paid route exists. It does not buy delisting as such: you pay to have your email shown publicly as the contact for that IP. Any address you use will receive abuse reports for it.
Want a hand getting this delisted? Here is how to write to a list's operator, or ask a person on our free SOS Hotline. Tell us the list and the IP or domain, and we reply within 48 to 72 hours.
A separate job: cleaning your list does not remove a listing. If you also want to know who on your list is safe to send to, clean your first 1,000 free.
The most useful email questions, once a month
One email a month. New questions worth reading, real deliverability changes (Gmail and Outlook updates, etc.), and any tool or report that landed since the last issue. No fluff, no upsell.
Contributors
Who worked on this answer
Every name links to their profile. Every company links to their site. Real people, real accountability.
