Hostkarma delisting: reading the colour codes and getting off the black list

Hostkarma, published by Junk Email Filter, is a reputation-graded DNSBL rather than a binary one. A single query to its combined zone returns a colour, and the colour is the whole diagnosis. The list is still active — public trackers show listings being added daily — and it ships enabled in some filtering configurations, which is why senders encounter it without ever having heard of it.

Read the return code

Query the combined zone with the octets reversed:

dig +short 9.113.0.203.hostkarma.junkemailfilter.com
dig +short -t txt 9.113.0.203.hostkarma.junkemailfilter.com

The separate black.junkemailfilter.com zone contains only the black entries, which is how most receivers consult it. Query it directly if you only care about the binary outcome:

dig +short 9.113.0.203.black.junkemailfilter.com

A 127.0.0.2 answer here is unambiguous — there is no white, yellow or brown result to confuse it with, because this zone only ever carries the black grade. Two consequences follow from the combined zone's broader design. First, a "listed on Hostkarma" row in a checker is ambiguous until you see the code — being on the white list also counts as a listing. Second, yellow and brown results are usually scoring inputs rather than outright blocks, so they degrade rather than refuse.

Why IPs end up black or brown

• Spam-trap hits, which for a shared or recycled IP may predate your use of it.
• Complaint volume from recipients of mail you sent.
• Mixed-stream sending — transactional mail, marketing and cold outreach from one IP. This is the classic route to yellow.
• Compromise. A hacked account, an open web form or a CMS relaying mail. Sudden black listings are often a security incident.
• Young or unknown space. Brown frequently means "we have no reason to trust this address yet", which includes a freshly allocated VPS IP.
• Infrastructure gaps. Missing or generic reverse DNS and a mismatched HELO make an unknown IP look worse.

Getting delisted

1. Confirm the colour and the object. Use the IP from a Received header of real sent mail. If you send through Google Workspace, Microsoft 365, SES, SendGrid, Mailgun or Postmark, the IP is the provider's and this is not yours to fix.
2. Find and fix the cause. Suppress hard bounces and complainers, purge unverified addresses, separate your mail streams onto different IPs or domains, audit SMTP auth logs and web forms for abuse, rotate credentials if anything looks off.
3. Correct reverse DNS. A PTR of mail.yourdomain.com with a matching A record and a matching HELO. Generic or missing reverse DNS keeps you looking like untrusted space.
4. Use the self-service removal. Junk Email Filter provides a courtesy removal on its site for senders who have resolved the problem. Entries also expire on their own a few days after the behaviour stops, so for a one-off incident the listing will clear without any request.
5. Re-query after an hour or two, and again the next day to confirm it did not come straight back.

What not to do

• Do not use the courtesy removal repeatedly. A self-service path exists as a convenience for senders who fixed something. Using it as a recurring reset, while the behaviour continues, is how a short listing becomes a sticky one.
• Do not panic over yellow. A mixed grade usually means stream separation, not an emergency. Move your bulk and outreach sending off the IP that carries transactional mail.
• Do not ignore brown on a new IP. It is a prompt to warm the address up properly rather than to start at full volume.
• Do not treat a white or NOBL result as a listing. Checkers that show it as one are miscounting.
• Do not stop at Hostkarma. It is a modest list by reach. If you are black here, check Spamhaus, Barracuda and SpamCop too — they are more consequential and the same cause usually feeds all of them.

Keeping the grade stable

The behaviours that hold a white or neutral grade are the same ones that hold reputation everywhere: verified recipients only, immediate suppression of bounces and complaints, one stream per identity, correct reverse DNS, and a volume curve that rises gradually instead of in steps.

MailPilot warms mailboxes at a controlled pace, checks the lists receivers consult against your sending domains and IPs, verifies SPF, DKIM and DMARC, and measures per-provider inbox placement daily — so a grade change shows up next to evidence of whether delivery actually moved.