Review IPv4 spam and security blocklists, then test email domain reputation in the dedicated checker below.
An IP blacklist check shows whether a public IPv4 address appears on DNS-based reputation lists used by mail administrators and security teams. A listing can affect email delivery, remote access and how some firewalls treat traffic from that address.
Use the email blacklist test below to check a sender domain or email address against public domain reputation lists, plus MX and SPF signals that affect deliverability.
The exposure scan is not a full penetration test. It only checks whether selected TCP ports accept connections from the Zerolink server. Pair results with DNS lookup, reverse DNS, and the port checker.
Match the delivery or security symptom first, then investigate only the sources that returned a listing.
Enter a public server, mail gateway or internet-facing IPv4 address.
The address is queried against public DNSBL zones and is not stored by this tool. Exposure checks are reachability tests only — not a full penetration test. See our privacy policy.
Check a sender domain or email address against domain reputation lists, MX records and SPF.
Domain reputation checks use public DNS lists. MX and SPF results help explain deliverability issues but are not blacklist listings themselves.
Interpret results carefully
Spam-focused DNSBLs and domain lists can influence whether mail is delivered, deferred or placed in spam.
Attack-reporting lists may flag addresses observed scanning, brute-forcing or abusing servers.
Open Telnet, SMB, RDP or database ports on the public internet are common breach entry points and should be restricted.
An IP blacklist or DNSBL is a reputation dataset that identifies addresses associated with spam, compromised systems, attacks or other unwanted activity.
Yes. Use the email blacklist test section below the IP checker. Enter a domain such as example.com or a full email address to query public domain reputation lists plus MX and SPF signals.
It checks reverse DNS and whether common high-risk TCP services are reachable from the Zerolink server. This helps spot accidental public exposure but is not a substitute for authorised penetration testing.
No. It only means these sources returned no listing at the time of the check. Firewalls and security providers may use private reputation data that is not publicly searchable.
A compromised device, abusive traffic, shared carrier-grade NAT or a previous user of a dynamic address may affect its reputation.
Open the official source link, review its evidence and follow its removal process. First stop the underlying spam, malware or server compromise.
This release checks IPv4 because the selected public DNSBL sources do not all provide equivalent IPv6 query support.
Many DNSBLs return addresses in the 127.0.0.0/8 range as listing codes. The exact code can indicate listing type or severity depending on the provider.
Spamhaus restricts automated commercial public-mirror usage. The tool links to the official Spamhaus checker so you can verify that important source directly.
Recheck after you fix the underlying issue and again a few hours later. Some lists update quickly, while others may take longer to reflect remediation.
Use these related checks when outgoing mail bounces, lands in spam or fails authentication.