IP Blacklist Check (DNSBL)

IPOK dev tools provide fast network diagnostics and data conversions, including IP purity, subnet risk, DNSBL blacklist, and ASN routing lookups.

Whether your server IP is on a spam / abuse blacklist (DNSBL) directly decides if mail reaches the inbox and whether requests get blocked. This tool checks 5 major blacklists at once (SpamCop, UCEPROTECT, Barracuda, S5H, Anonmails) and shows exactly which one hits.

Being listed usually means the range was abused — common for datacenter / proxy / VPS IPs, often by association with bad neighbours in the same block. Queries go live via Cloudflare DoH, entirely in your browser. Blacklists alone aren't the full picture — IP purity needs multiple sources.

DNSBLs (spam / abuse blacklists) are queried live via Cloudflare DoH, locally, never uploaded. Being listed usually means the range was abused — common for datacenter / proxy IPs.

Check this IP's full purity and multi-source risk score →

Check your own IP — purity, risk score, native vs datacenter, leaksCheck IP →

FAQ

What happens if an IP is blacklisted?

Mail you send is more likely bounced or spam-filed, and sign-up / unlock / checkout more easily trigger verification or get blocked.

Why is my datacenter / VPS IP listed?

Blacklists often operate at the IP-range level; if anyone in the same block spams or abuses, the whole range can be flagged and your IP suffers by association.

Can I check IPv6?

DNSBLs are essentially IPv4-only, so this tool checks IPv4 only. For IPv6's overall risk, use this site's IP check.