017.005

DNS Limits & Flattening

The "Too Many Lookups" error. The SPF standard has a "magic" limit: it cannot require more than 10 DNS lookups to resolve. This section covers flattening—a service that "pre-calculates" all the IPs in your SPF record to keep you under this critical limit.

6 questions in this topic

What are the common DNS limitations for email records? (e.g., SPF lookups, TXT record length) How does the SPF 10-lookup limit work technically? What happens if I exceed DNS limits? What is SPF flattening and how does it help? Are there risks associated with SPF flattening? Are there limits on the number of TXT records per domain?