SpamAssassin rule
RDNS_DYNAMIC
Reverse DNS looks like a home connection
+0.363 points
Combination of other tests (meta rule)
What RDNS_DYNAMIC means
The sending IP's reverse DNS name looks like a dynamic or residential address (it contains the IP, "dyn", "pool" and similar).
The rule's description in SpamAssassin: “Delivered to internal network by host with dynamic-looking rDNS”
How to fix it
Do not send directly from a home or office internet connection. Relay through your provider's SMTP server or an email service.
Does your email trigger RDNS_DYNAMIC?
Send it to a free test address: we run SpamAssassin, check SPF, DKIM and DMARC and show every rule with a fix.
Open the email spam checkerRelated rules
FORGED_GMAIL_RCVDGmail address sent through non-Gmail servers
FREEMAIL_FORGED_REPLYTOFree-mail Reply-To on a different From
FREEMAIL_FROMSent from a free email address
FREEMAIL_REPLYTODifferent free-mail addresses in From and Reply-To
FROM_FMBLA_NEWDOMFrom domain registered in the last 7 days
FROM_FMBLA_NEWDOM14From domain registered in the last 14 days
FROM_FMBLA_NEWDOM28From domain registered in the last 28 days
FSL_HELO_NON_FQDN_1HELO is not a full host name
HEADER_FROM_DIFFERENT_DOMAINSFrom and envelope sender use different domains
Frequently asked questions
What does RDNS_DYNAMIC mean?
The sending IP's reverse DNS name looks like a dynamic or residential address (it contains the IP, "dyn", "pool" and similar).
How do I fix RDNS_DYNAMIC?
Do not send directly from a home or office internet connection. Relay through your provider's SMTP server or an email service.
How many points does RDNS_DYNAMIC add?
0.363 points in the default SpamAssassin ruleset (network tests on, Bayes off). A message is treated as spam from 5.0 points. Mail servers can change scores locally.