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IP reputation check

Checks one address against the blocklists mail providers and abuse desks genuinely consult, and links you straight to the removal form for anything that has it. No account. We are also not going to ask for your email before showing you the answer.

One IPv4 address at a time. The portal scans whole ranges on a schedule and files the delistings for you.

What a listing actually costs you

Blocklists get consulted at the moment a connection is made. There is no warning and no spam folder. The receiving server refuses the connection, the sender gets a bounce, and almost nobody reads bounce messages closely enough to work out why.

So delivery does not gradually degrade. It stops.

And it reaches further than email. Abuse desks, fraud systems, cloud providers and content networks all pull from the same feeds when they decide whether to rate-limit you, challenge you, or block you outright.

Why space you just acquired is already listed

Reputation sticks to the address, not to whoever holds it. Whatever the previous occupant did with those addresses came along with them, and some lists keep records for months after the behavior stopped.

This is comfortably the most common unpleasant surprise for anyone buying or leasing address space. It is also why we scan a block before offering it rather than after delivering it.

Getting delisted is the easy part

Most lists will remove an address if you ask. Most will also put it straight back if whatever triggered the listing carries on.

The work worth doing is finding the cause: a compromised host, a relay somebody left open, a customer sending mail they should not be. Once that is sorted, removal is paperwork.

Common questions

Why do some lists say they could not be checked?

Several of the big ones refuse queries from shared public resolvers and want you on a registered data feed instead. A free tool runs into that wall. Our own scanning uses dedicated resolvers and keys, which is why it does not.

How often should an address be checked?

Checking once tells you about today. What you usually want to know is whether a listing appears at all, and that needs watching rather than checking. Catch one the week it happens and it is a support ticket. Find it three months later and it is a reputation problem.

One address at a time only gets you so far. Reputation is really a property of a whole range. The Prefixx portal scans every address in the ranges you hold on a schedule, scores each range, tracks how it moves, and tells you the moment a listing shows up. Where the listing did not come from your own traffic, our team files the removal and confirms it came off. That runs at no charge for leased space and after a transfer. Reputation monitoring →