How to check if your IP is blacklisted

Step 1: Find the right IP address

Blacklists list the IP that sends your mail, which is often not the same as your website's IP.

1. Send an email from your normal account to a personal address.
2. Open it and view the original message / full headers.
3. Find the Received: lines. The first one added by the recipient's server shows the IP that connected to it — that's your sending IP.

If you use Microsoft 365, Google Workspace or another big provider, you share their sending infrastructure, and they manage its reputation. Blacklist checks matter most for your own mail server, a VPS, or shared hosting that sends mail directly.

Step 2: Run the check

Enter the IP in the Blacklist Checker. You can also enter a hostname such as mail.example.co.za — the tool resolves it to its IPv4 address first.

Step 3: Read the results

• Clean — the list returned no entry for the IP.
• Listed — the list returned a positive listing code.
• Unavailable — the list didn't give a usable answer. Some lists, notably Spamhaus, refuse queries that arrive through big public resolvers and return an error code instead. Our checker recognises those codes and shows them as unavailable rather than wrongly reporting a listing. Check those lists on their own websites.

Which lists matter most?

Listings on widely used lists — Spamhaus in particular — have the biggest effect because many mail systems use them directly. Some smaller lists are rarely used for blocking, and some (such as UCEPROTECT's level 2 and 3) list whole network ranges, so you may appear because of a neighbour's behaviour. Focus on fixing the cause, then on the lists that your recipients' providers actually use.

What if you're listed?

Don't rush to request removal. First find out why — a compromised mailbox, an infected website sending spam, an open relay, or a bad mailing list — and fix it. Then follow our guide to removing an IP from a blacklist.