Infrastructure Checks

10% of your score. These look at the sending plumbing — usually handled by your ESP or mail host, but worth confirming.

TLS Encryption — 3 pts

Checks the email was delivered over an encrypted TLS connection. Why it matters unencrypted mail is penalized and exposes message contents in transit. Fix ensure your sending service uses TLS (all reputable ESPs do); if you self-host, enable STARTTLS.

HELO/EHLO Match — 3 pts

Checks the sending server’s HELO/EHLO hostname matches its reverse DNS. Why it matters a mismatch is a common signal of misconfigured or suspicious senders. Fix configure the HELO hostname to match the IP’s PTR record (managed for you on shared/ESP IPs).

IP Type Detection — 2 pts

Checks what kind of infrastructure the sending IP belongs to (e.g. proper mail infrastructure vs. residential/dynamic ranges). Why it matters mail from consumer or dynamic IPs is widely distrusted. Fix send from a dedicated mail service or properly classified sending IP.

Domain Suffix Check — 2 pts

Checks the sending domain’s TLD against low-reputation suffixes. Why it matters certain cheap or heavily abused TLDs carry built-in suspicion. Fix send from an established domain on a mainstream TLD rather than a throwaway one.