Junk Email Filter Hostkarma Blacklist
Hostkarma is an IP and hostname blacklist (or blocklist) using a color-coded system to identify spam, legitimate mail, and mixed sources in one query.
Updated on 17 Jun 2026: We updated this guide with Hostkarma lookup syntax and clearer delisting steps.
Summarize with
Check if you are listed on Junk Email Filter Hostkarma Blacklist
And 143 other blocklists.
Spamhaus
0Spam
Cisco
NoSolicitado
URIBL
abuse.ro
ALPHANET
Anonmails
Ascams
BLOCKEDSERVERS
Calivent Networks
EFnet
JustSpam
Kempt.net
NordSpam
RV-SOFT Technology
Scientific Spam
Spamikaze
SpamRATS
SPFBL
Suomispam
System 5 Hosting
Team Cymru
Validity
www.blocklist.de Fail2Ban-Reporting Service
ZapBL
2stepback.dk
Fayntic Services
ORB UK
technoirc.org
TechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftWhat is the Junk Email Filter Hostkarma blacklist?
The Junk Email Filter Hostkarma blacklist is a DNS-based blocklist (DNSBL) that classifies email sources by reputation instead of using a simple listed or not listed result. Junk Email Filter states that Hostkarma is intended to block spam while helping legitimate senders deliver mail after compromised accounts, infected devices, or server misconfigurations are fixed. The list is a reputation system for IP addresses and hostnames.
Its single DNS lookup can return multiple status codes, so mail server admins can treat a sender as trusted, blocked, mixed, or unsuitable for further blacklist checks without making separate DNSBL queries. Hostkarma uses color-based categories: whitelists for trusted non-spam, blacklists for known spam, yellow lists for mixed sources, brownlists for spam sources that have not reached full blacklist status, and NOBL entries for sources that should not be blacklisted. It also supports name-based lookups using Forward Confirmed reverse DNS (FCrDNS), which is harder to spoof than an IP address alone.
The lookup zone, hostkarma.junkemailfilter.com, returns these common results:
- 127.0.0.1 (whitelist) means a trusted source of non-spam email. Messages can be accepted without further checks.
- 127.0.0.2 (blacklist) means a known source of spam. Messages can be blocked.
- 127.0.0.3 (yellowlist) means a mixed source that sends both spam and non-spam, such as large webmail or ISP mail systems. The recommended use is to bypass other IP-based blacklists for these sources while still applying content and policy checks.
- 127.0.0.4 (brownlist) means the source has sent spam but has not reached full blacklist status. Treat it as a scoring signal.
- 127.0.0.5 (NOBL) means the IP is not a spam-only source, and no further blacklist checks are necessary.
How do I check a Junk Email Filter Hostkarma blacklist listing?
For an IP lookup, reverse the IP octets and append the Hostkarma DNS zone. For example, 1.2.3.4 becomes 4.3.2.1.hostkarma.junkemailfilter.com. For a hostname lookup, append the same zone directly to the hostname. A positive response returns one or more 127.x.x.x codes. No response means Hostkarma has no matching public listing for that query.
Hostkarma lookup examplesBASH
dig 4.3.2.1.hostkarma.junkemailfilter.com dig example.com.hostkarma.junkemailfilter.com
Treat 127.0.0.4 and the experimental return codes as scoring signals, not automatic rejection rules. Hostkarma documentation says blacklist data lives about 5 days, so a clean source can fall off after spam stops, except for permanent entries.
Who runs the Junk Email Filter Hostkarma blacklist?
Junk Email Filter operates the Junk Email Filter Hostkarma blacklist. Their system combines public DNS reputation data with spam filtering logic that classifies sources in several categories instead of only pass or block. That model supports different handling for spam-only sources, known-good senders, and mixed senders.
They publish Hostkarma as a public DNS zone, accept both IP and hostname queries, send automated notices to alert spam sources of problems, and accept feedback through the removal contact. The public data helps receiving servers block spam, skip unnecessary checks for trusted sources, and avoid false positives against mixed or known-good senders.
What's the impact of being listed on the Junk Email Filter Hostkarma blacklist?
The impact of being on the Junk Email Filter Hostkarma blacklist is usually lower than a listing on a heavily adopted blocklist because Hostkarma is used most often by smaller internet service providers, hosting providers, and administrators who choose its color-coded model. It does not mean every mailbox provider will reject your mail. It does mean a receiving server that checks Hostkarma can reject, score, or route mail differently when it receives 127.0.0.2 or 127.0.0.4.
Do not treat a Hostkarma listing as cosmetic. Check the sending IP, recent spam complaints, bounce patterns, open relays, compromised accounts, and authentication results. In Suped, use DMARC aggregate reporting to confirm which services are sending for your domain and whether SPF, DKIM, and DMARC are passing before you request delisting.
How do I get removed and delisted from the Junk Email Filter Hostkarma blacklist?
Junk Email Filter provides a courtesy removal form for senders who were wrongly listed or have fixed the problem. Before requesting delisting from this blacklist (or blocklist), fix the source of the spam: disable compromised accounts, remove malware, close open relay behavior, correct reverse DNS, and confirm that only authorized systems send for your domain.
After the fix, submit the IP through the removal form. The removal is short term. If Hostkarma detects more spam, the IP will be relisted. Junk Email Filter also states that blacklist data normally lives about 5 days, so clean traffic after remediation can resolve some listings without a manual request. If the listing is an error or you want whitelisting considered, contact remove@junkemailfilter.com.
