Blacklist checker · Folderly Lens

Find blacklist risk before one domain poisons the campaign.

Paste sending domains and Lens checks visible DNSBL exposure together with authentication and MX signals. The result is not just listed/not listed; it is what to retire, fix, or keep.

7 RBL checks in the free scanner
KILL when risk follows the domain
CSV register in the full audit

Run the blacklist check

Open the full Lens scanner with verdicts and a fix plan.

Enter at least one valid domain.

Blacklist hits are not isolated incidents

Shared fate

A listed domain can damage campaign reputation even when other records look acceptable.

Retire vs fix

Some domains should be rebuilt, not polished. Lens makes that call explicit.

Monitor drift

New listings are silent until performance drops. Weekly monitoring catches them early.

How to use the blacklist result

If a domain is listed

Pause sending from that domain before it drags down the rest of the campaign. Lens marks severe listing exposure as a retire/rebuild task, not a cosmetic fix.

If it is clean today

Save the scan as a baseline. Blacklist risk changes over time, especially when domains come from the same reseller batch or shared outbound footprint.

If the result is unclear

Do not treat unresolved as clean. Retry the scan or request the full audit so the domain is reviewed before it enters active sequences.

Domain blacklist checker FAQ

What does Lens check?

The public scanner checks multiple DNSBL-style signals and combines them with SPF, DMARC, and MX posture before it recommends KILL, REHAB, or KEEP.

Should I delist or retire?

Delisting can work only if the root sending pattern is fixed. If the domain has cold-email abuse history, retirement is often safer than polishing it.

Can one listed domain hurt others?

Yes. Domains in the same campaign, reseller batch, or infrastructure pattern can create shared-fate risk even when only one domain is visibly listed.