Compliance
NIS2 Entity Registration in Poland: October 2026 Deadline
The Wykaz KSC registration deadline passed on 3 October 2026. See what late filers should do, the registration paths, and what the penalties actually are.
12 Aug 2026 Read →
Free tool
Can someone impersonate
your email?
Enter your company domain and we'll check its SPF, DKIM and DMARC records - the three DNS settings that decide whether a criminal can send email pretending to be your company. The test runs in your browser, reads only public data, and stores nothing.
Advanced options (DKIM selector)
Lookups go straight from your browser to public DNS resolvers. We send no email, need no passwords, and store none of the domains you check.
What it means
Three records that keep impersonators away from your domain
- SPF - who may send on behalf of your domain
- A list of servers allowed to send your mail. With no SPF (or a broken one) receivers can't tell your mail from a forgery. The strongest ending is
-all. - DKIM - a cryptographic signature on your mail
- A digital signature attached to each message that proves the content wasn't altered in transit and really came from your domain.
- DMARC - what to do with mail that fails the checks
- Your instruction to receivers: reject (
p=reject), send to spam (p=quarantine) or just observe (p=none). Without DMARC, impersonating mail usually gets through.
Why it matters
The most common start of wire-transfer fraud
In a BEC attack (Business Email Compromise) a criminal sends your client or your bookkeeper an email that looks like yours - "our bank details changed, please pay here." If your domain has no valid SPF and DMARC, that forgery looks authentic and lands without warning.
Correctly configured records block the impersonation at the source. It's one of the cheapest, fastest ways to close a real attack path - especially for an accounting firm. More in SPF, DKIM and DMARC explained for accounting firms.
Email is only one way in
This test checks email. A free PreScan shows your whole attack surface: open ports, remote-access services, certificates and leaked passwords - in 24 hours, with no access to your systems.
About this test
Common questions
- Does this test need access to my mailbox?
- No. It reads only your domain's public DNS records (SPF, DKIM, DMARC, MX). We never sign in anywhere, never send test email, and never need a password.
- Do you store the domains I check?
- No. The lookups run directly in your browser against public DNS resolvers (Cloudflare, Google). Nothing reaches CyberCerber servers - we don't log or store the domains you check.
- What are SPF, DKIM and DMARC?
- Three DNS records that together decide whether someone can impersonate your email address. SPF lists which servers may send for your domain; DKIM signs your mail cryptographically; DMARC tells receivers what to do with mail that fails those checks.
- Why does this matter for an accounting firm?
- Because a missing DMARC record is the most common setup behind wire-transfer fraud (BEC): a criminal sends your client - or you - an email that looks like yours, asking to update the bank details. Correct SPF and DMARC block that impersonation at the source.
- The test shows a problem - what now?
- DNS records are changed at your domain registrar or hosting provider. Your IT person can do it, or we can map your whole attack surface in a free PreScan and hand you the exact record values.
- Does 'no DKIM found' mean I don't have it?
- Not necessarily. DKIM uses a selector that is often custom and only visible in the headers of a sent message. The test probes the most common selectors; a miss doesn't prove DKIM is absent.