Operational visibility foremail delivery infrastructure.
Understand authentication, routing, reputation, and infrastructure trust. Send a test message and on.bo surfaces every signal across the delivery path.
Send a test email to
Inbound capture goes live once DNS is wired (see docs).
Visibility into every layer of email trust infrastructure
Authentication, TLS, routing, reputation, and your domain's full mail footprint — observed in one operational view.
Authentication
SPF, DKIM, DMARC, ARC, BIMI — full validation with alignment checks and ready-to-paste fixes.
TLS & SSL
STARTTLS, cipher, cert chain, MTA-STS, DANE/TLSA, and TLS-RPT — checked end to end.
Sending infrastructure
Reverse DNS, FCrDNS, HELO, IP geo/ASN, IPv6 — diagnose the path your mail takes.
40+ blacklists
Spamhaus, Barracuda, SORBS, SpamCop, UCEPROTECT — checked with per-list delist links.
Subdomain visibility
Find every mail-related subdomain and detect which ESP each one points to.
Content & headers
SpamAssassin scoring, header hop map, List-Unsubscribe, attachments, dark-mode preview.
How it works
Grab your address
We give you a unique throwaway address like test-xxxx@on.bo.
Send your email
Send from your CRM, marketing tool, transactional app, or just your inbox.
Get a full report
We score deliverability 0–10 and tell you exactly what to fix, with copy-paste DNS.
Forward a suspicious email. Get a trust report back.
Forward anything sketchy to spam@on.bo and we'll reply with a short report: sender authentication, infrastructure age, web presence, and a shareable link you can send to anyone.
Standalone tools
Already know what's broken? Jump straight to the right tool.
SPF Checker
Validate SPF syntax, includes, and the 10-lookup limit.
SPF Generator
Build a clean SPF record from your sending services.
DKIM Checker
Look up DKIM public keys by selector and validate them.
DMARC Checker
Inspect DMARC policy, alignment, and reporting addresses.
DMARC Generator
Generate a DMARC record with a safe rollout strategy.
BIMI Checker
Validate BIMI record, SVG logo, and VMC certificate.
BIMI Generator
Generate a BIMI TXT record for your logo.
MX Lookup
Look up MX records, priorities, and resolved IPs.
Blacklist Checker
Check IPs and domains against 40+ RBLs in one click.