Email Blacklist Check

Why we show every list, not just the hits

"You are not blocklisted" is a claim nobody can check. It does not say how many lists were consulted, whether they answered, or whether the important ones were among them. Two lists queried and twenty read the same way in a summary and mean entirely different things.

So every list appears with its own answer: listed, clean, declined our query, or did not respond. That last distinction matters more than it looks. Most blocklists limit free use and refuse queries from resolvers they have not authorised, replying with a reserved code instead of a verdict. Treating that as a pass would hand out clean bills of health on no evidence; treating it as a hit would accuse everyone. It is neither, and it is labelled as neither.

What the roster is and how it was chosen

Seventeen lists: fifteen that publish data about addresses and two about domain names. Each one was queried with its own documented test point before being included, and with a control value that must come back clean. Only lists that answered correctly to both are here.

That check is not ceremony. Blocklists shut down, and a dead zone does not announce itself — it returns the same "no such name" that means "not listed". A list that has quietly disappeared will clear every address you ever check, forever, and look exactly like a working one while doing it. SORBS closed in 2024 and still appears in roster after roster of tools that never went back to look.

The lists that actually block mail

They are not equal. A handful decide whether large receivers accept your connection at all; the rest feed scoring systems where a hit costs you a fraction of a point.

• Spamhaus ZEN — the one that matters most. It combines SBL (known spam sources), XBL (compromised machines), CSS and PBL. A ZEN listing gets mail rejected outright at a large share of the internet.
• Barracuda — used by Barracuda appliances, which sit in front of a great many corporate mail systems.
• SpamCop — fed by user reports and expires automatically, so listings come and go faster than elsewhere.
• Spamhaus DBL and SURBL — about domains rather than addresses. They catch the name in your links even when the sending server is spotless, which is what happens after a shared shortener or a compromised landing page gets abused.

PBL is not what people think it is

Of all the listings, this is the one that causes the most confusion and the most wasted effort. A PBL entry does not say you sent spam. It says the address belongs to a range that should not be sending mail directly — a home connection, a dynamic pool, consumer broadband.

There is usually nothing to appeal, because the listing is accurate. If you are sending from a dynamic address, that is the problem, and removal would not fix it: receivers distrust the range, not the entry. The answer is to send through a mail server with a static address and proper reverse DNS, or through your provider's relay.

This is also why a PBL hit shows up so often on tests run from an office or a laptop. The connection is doing exactly what PBL describes.

Getting removed, and staying removed

Fix the cause first. A listing removed while the cause remains comes back within days, and repeated removals from the same address are themselves a signal. The usual causes, in order of how often they turn out to be it: a compromised mailbox sending through your server, a web form with no rate limit, a list bought or scraped rather than collected, and a script that retries failed deliveries in a loop.

Then use the list's own removal page — each hit above links to the right one. Spamhaus handles most automated removals in hours; SpamCop entries expire on their own if the sending stops; Barracuda reviews requests by hand.

What a clean result does and does not prove

It proves that no receiver will refuse your connection because of a published listing. That is a real and necessary thing, and it is roughly where its usefulness ends.

Mail that passes every blocklist still lands in spam when the domain has no authentication, when the reverse DNS does not match, when recipients mark it as unwanted, or when the content reads like a promotion. The blocklist check tells you the door is not bolted. It says nothing about whether you will be invited in.