What is HostKarma?
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HostKarma is Junk Email Filter's list, and covers hostkarma.junkemailfilter.com (IPs and domains) and black.junkemailfilter.com (IPs).
What the operator says
"what servers are sending spam, nonspam, or a mix of spam and nonspam" Junk Email Filter, Spam DNS Lists, read 1 Nov 2026.
What it really measures
HostKarma scores servers both ways, so not every answer is bad news. Trusted servers feed it counts of spam and non-spam from each host, and the mix decides the colour. The number the lookup returns tells you which:
| Number | Colour | What it means |
|---|---|---|
| 127.0.0.1 | White | Trusted, only good mail seen |
| 127.0.0.2 | Black | Only spam seen. This is the listing that blocks |
| 127.0.0.3 | Yellow | A mix. Big free mail providers sit here, and the operator says these hosts should not be blocked |
| 127.0.0.4 | Brown | All spam so far, not enough yet for black. On name lookups, the same number means a domain list |
| 127.0.0.5 | NOBL | Not a spam-only source, so other lists need not be checked |
A lookup can also return other numbers about behaviour and domain age. They do not change the colour.
Why you might be there
Black catches servers sending only spam, which the operator says generally means infected machines. It is built from spam traps and fake mail server records, so one hit can list a server fast.
Yellow usually means your mail shares a platform with other senders. That is no accusation.
What to think about
Read the colour before you do anything. Only black needs fixing today, and brown is a warning. If an infected machine is still sending, a removal will not hold, so look there first.
How to get off it
Clear the cause and wait. Black entries last about 5 days, so a listing drops off by itself about 5 days after the spam stops. The operator also keeps some permanent blocks, and those do not drop off.
For something faster, use the removal form. It is a courtesy and short term, and more spam lists you again. If you think you were listed in error, email remove@junkemailfilter.com.
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.
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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.
