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SPF Lookup Limit

Verifies the SPF record stays under the DNS lookup limit defined by RFC 7208 §4.6.4 (10 lookups maximum).

This is a frequent silent failure. Every time you add a new email vendor via include:, you consume more lookups, and once you exceed 10 the SPF record is treated as permerror and most receivers behave as if you have no SPF at all.

Applies to: URIBL and URI hosts.

How It Works​

We fetch your SPF record and walk every DNS-lookup mechanism:

  • include:
  • redirect=
  • a (and a:, a/)
  • mx (and mx:, mx/)
  • ptr (and ptr:)
  • exists:

Each one consumes one lookup. We follow include: and redirect= recursively (with cycle detection) and total the lookups across the entire chain.

Fails On​

  • Total lookup count exceeds 10.
  • A cycle is detected in the include chain.