Get your sending IP off a blocklist
A DNS blocklist (DNSBL) like Spamhaus or Barracuda flags IPs and domains seen sending spam. A listing can silently tank delivery across many receivers at once. The fix is to address the cause first, then request delisting.
Why mailbox providers enforce this
Major receivers query these lists in real time. A Spamhaus SBL/XBL listing in particular can mean outright rejection. Delisting before fixing the root cause just gets you re-listed — providers track repeat offenders harder.
How to fix it
- Identify which list and why — each blocklist publishes a lookup and a reason code.
- Fix the cause: a compromised account, an open relay, a bad mailing list, or a sudden volume spike.
- Use the list's official removal portal (e.g. Spamhaus removal, Barracuda removal request). Never use paid 'delisting services'.
- If you send from shared infrastructure (Google, Outlook, SES relays), the IP reputation isn't yours to fix — focus on your domain reputation and authentication instead.
- Re-test after delisting to confirm you're clear before resuming volume.
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FAQ
How long does delisting take?
Automatic listings often clear within 24-48 hours once the cause stops. Manual reviews can take longer. Repeated re-listings extend the cooldown.
My mail comes from Gmail's servers but I'm 'blacklisted' — why?
If you send via a shared provider relay, a tool may be checking that shared IP. Shared-relay IP reputation is managed by the provider, not you — it's not a meaningful signal for your domain.
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