DNS blocklist (DNSBL) check

Whether the address the site is served from appears on public DNS blocklists. A listing gets mail from that host filtered and can follow the site around.

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DNS blocklists (DNSBL) are public databases of IP addresses and domains seen sending spam, hosting malware or phishing. Mail servers, firewalls and filters query them in real time. If the address your site is served from, or your domain itself, is listed, mail from it lands in spam or is refused, and some corporate networks block the site. A listing often comes from a compromised form, a hacked plugin, or a previous tenant of a shared IP.

How SiteScan checks it

The scanner looks up the server's IPv4 address in Spamhaus ZEN, SpamCop and UCEPROTECT, and the registered domain in Spamhaus DBL, SURBL and URIBL. Many lists refuse queries from public resolvers; a refusal is not counted as a clean result, which is why the green row says how many lists actually answered. Google Safe Browsing is counted among them when it is available. A listing turns the row red and names each list with the reason it gave.

What to do if listed

Find and fix the cause first: check mail logs, contact forms, outdated plugins and outgoing traffic. Then use each list's own lookup page to request removal — Spamhaus and SpamCop delist quickly once the problem stops; some lists expire entries on their own. On shared hosting, ask the provider for a clean IP. For mail, also set up SPF and DMARC.