Your sending IP address is on a blacklist

What it means

Every email is sent from a server with an IP address, a number like 203.0.113.10. Blacklists (also called blocklists or DNSBLs) are public lists of IP addresses that sent spam or behaved suspiciously. Many receiving servers check them before accepting an email.

Why it matters

It depends on the list. Delivmail sorts them by impact:

• High impact (for example Spamhaus, Barracuda, SpamCop): used by many providers. A listing can cause rejections or spam placement.
• Low impact: rarely used by major providers like Gmail or Outlook. Worth knowing, rarely urgent.

How to check

Send a test email from the home page: the report checks the IP that actually delivered your email and tells you whether it looks like your own server or a shared provider. You can also look up any IP address on the Blacklist lookup page at /blacklists.

First: is it your IP?

Shared IP (Google, Microsoft, a newsletter tool, your web host's mail server)

If you send through Gmail, Outlook or a big email service, the IP is shared with many other customers. A listing is usually caused by someone else, and the provider is responsible for it.

• Do not request removal yourself: you do not control this IP.
• Check that your own account is not hacked: unexpected sent emails, unknown logins, strange forwarding rules.
• If your recipients report problems, contact your provider's support with the Delivmail report.
• For large volumes, ask your provider about a dedicated IP address.

Your own server or a dedicated IP

Here the listing is about your own sending. You must find and fix the cause before asking for removal, or you will be listed again quickly.

How to fix it (own server)

1. Find the cause. The most common ones:
   • A hacked email account sending spam (change passwords, enable two-factor login).
   • A hacked website or plugin sending email in the background.
   • A contact form abused by bots (add a captcha).
   • A bought or old contact list full of invalid or trap addresses.
   • A badly configured server that relays mail for anyone ("open relay").
2. Stop the problem. Clean the server, block the abused account or form, and check your outgoing queue is empty of spam.
3. Read the listing reason. Each blacklist has a lookup page that explains why the IP is listed and how to request removal.
4. Request removal on each list's website, starting with the high-impact ones. For Spamhaus, use check.spamhaus.org.
5. Be patient. Some lists remove you within hours, others expire automatically after a few days without spam.

Prevent it from happening again

• Only send to people who asked for your emails, and remove addresses that bounce.
• Make unsubscribing easy.
• Set up SPF, DKIM, DMARC and reverse DNS correctly.

Need a hand? Blacklist removal help is available in the paid Delivmail dashboard.

Check that it is fixed

Check the IP again on the Blacklist lookup page, then send a new test email from the home page. The blacklist section should be clean.