New email deliverability checks are available for RBL Monitoring profiles. These checks verify the DNS and TLS configurations that receiving mail servers evaluate to score inbound mail, catching the misconfigurations that quietly cause mail to land in spam or get rejected.
Available Checks
IP-based checks (IPv4 and IPv6 hosts):
- Reverse DNS (rDNS): the IP has a PTR record
- Forward-Confirmed Reverse DNS (FCrDNS): the PTR resolves forward back to the original IP
- Generic PTR Pattern: PTR doesn't look like a dynamic / consumer hostname
- PTR Hostname Format: PTR has at least 2 labels and a valid alpha TLD
Domain-based checks (URIBL and URI hosts):
- MX Health: MX records exist and at least one MX target resolves
- SPF Record: domain publishes a valid SPF record
- SPF Record (Strict): SPF record uses an enforcing policy (
-allor~all) - SPF Lookup Limit: SPF stays within RFC 7208's 10-lookup cap
- DMARC Record: domain publishes a valid DMARC record
- DMARC Record (Strict): DMARC record uses an enforcing policy (
p=quarantineorp=reject) - TLS-RPT Record: domain publishes a TLS Reporting record
- MTA-STS Policy: domain publishes a valid MTA-STS policy
- BIMI Record: domain publishes a valid BIMI record
How to Enable
All deliverability checks are opt-in. Even with "Stay in-sync with us" enabled, none of these run unless you specifically enable them on a Monitoring Profile.
Go to RBL Monitoring > Monitoring Profiles > Data Sources, switch to the Email Deliverability tab, and check off the ones you want.
We recommend creating a dedicated "Email Servers" profile for your mail-sending hosts so that non-mail hosts don't generate noise alerts for checks that don't apply to them.
Failures trigger the same alerts and webhooks as blacklist listings, so they integrate into your existing notification pipeline.