Reverse DNS looks like a generic provider-assigned name
What this check looks for
Your mail server's reverse name looks automatically generated rather than chosen — the sort of name a provider mints for a whole block of addresses. Some receivers treat that as a sign of an unmanaged host.
Why it matters
A generic reverse name is one of the oldest heuristics in spam filtering, because dial-up and consumer broadband ranges were named that way. A named mail server is a small, cheap signal that a human is responsible for it.
When the check passes, your report says: “The reverse DNS name looks chosen, not machine-generated”.
What it costs your score
When this check fails it removes 5 points from your Email transport score, before the status, confidence and repeat multipliers are applied. Email transport carries a weight of 8 in the overall score.
It shares the email-transport.rdns family ceiling of 25 points: however many findings that family produces, together they cannot remove more than that from Email transport. One underlying problem showing up in several places is still one problem.
- Severity
- low
- Default confidence
- medium
- Status when triggered
- warn
- Deduction
- 5 points
- Family cap
- email-transport.rdns · 25
- Category
- Email transport
- Module
- Email rdns
- Fix owned by
- ip provider
- In the ruleset since
- 2026.09
How to fix it
Ask the address's owner to set the reverse name to your mail server's own hostname.
A named server is treated as a managed one; a pool-style name is treated as a consumer host.
Choose the hostname the server should be known by, normally
‹mx host›.Publish a forward A/AAAA record for it pointing at ‹address›.
Ask the provider that owns ‹address› to change the PTR from
‹ptr names›to that hostname.If the provider will not change it — some consumer ISPs will not — send outbound mail through a relay or a provider that will, rather than directly from this address.
How to confirm it worked
dig +short -x ‹address› — expect a name you chose, not one containing the address.
A named slot like ‹domain› — and the braces left in the configuration below — is filled in with your own values when this rule appears on a report.
Technical detail
The reverse name for ‹address› is ‹ptr names›. ‹generic reason›. This is a heuristic, not a protocol rule: a receiver's opinion of the name is what actually matters, and policies differ. It is reported as a warning so it can be weighed rather than obeyed.
Standards and references
Test this on your domain
Run the check that produces this finding, on its own, against any domain.