Validate SPF records according to RFC 7208. Expands all include lookups and checks DNS lookup count (max 10 allowed).
| Mechanism | Description |
|---|---|
| all | Matches all addresses (usually at end with - or ~) |
| include | Include SPF record from another domain (counts as lookup) |
| a | Match if IP matches A/AAAA record (counts as lookup) |
| mx | Match if IP matches MX record (counts as lookup) |
| ip4 | Match IPv4 address or CIDR range |
| ip6 | Match IPv6 address or CIDR range |
| ptr | Reverse DNS lookup (deprecated, counts as lookup) |
| exists | Check if domain has A record (counts as lookup) |
| redirect | Use SPF record from another domain instead |
| exp | Explanation string for failures |
| Symbol | Result | Meaning |
|---|---|---|
| + | Pass | IP is authorized (default if omitted) |
| - | Fail | IP is not authorized, reject |
| ~ | SoftFail | IP is not authorized, but accept |
| ? | Neutral | No policy statement |