SPF Record Syntax

Quoted on this wiki

Every place a page here uses this source, in the order the words come in it.

1. In this sub section “delivery tips’ of the Gmail postmaster site, it is recommended to; “Use separate email addresses” Send mail from different domains and/or IP addresses

   In Domain and mailbox architecture

2. Use separate email addresses “Send mail from different domains and/or IP addresses” In summary, you should not run in to the 10 lookup maximum. If you do, we’ve outlined some additional strategies and knowledge-base materials on how to navigate.

   In Domain and mailbox architecture

3. As it has become somewhat commonplace for any single organization to authorize a large number of disparate netblocks (due to the outsourced nature of email infrastructure), there remains what seems like the constant and unnecessary encroachment on the ten maximum lookup.  This limit however remains entirely practical and should be observed to ensure timely delivery and favorable inbox rates. Further, the solution to avoid the limit is squarely addressed by other mainstream email best practices, long encouraged by major inbound receivers such as Gmail and Yahoo. “The single most practical solution to avoid the ‘too many lookups’ issue is to make use of sub-domains. As each discrete sub.domain is afforded its own ten lookup maximum, SPF is effectively boundless. Example: hello.com is permitted ten lookups + sub.hello.com is permitted ten lookups. Plainly put, you should never run in to the ten maximum lookup condition if you are correctly segmenting different mail streams (eg. transactional, corporate, marketing, etc.) on to discrete name space.” In this sub section “delivery tips’ of the Gmail postmaster site, it is recommended to;

   In Domain and mailbox architecture

4. ? Neutral “If a mechanism results in a hit, its qualifier value is used. The default qualifier is “+“, i.e. “Pass”. Mechanisms are evaluated in order. If no mechanism or modifier matches, the default result is “Neutral”.” More in-depth information on the differences between “~” and “–” can be found here

   In SPF records

5. More in-depth information on the differences between “~” and “–” can be found here “If a domain has no SPF record at all, the result is “None”. If a domain has a temporary error during DNS processing, you get the result “TempError” (called “error” in earlier drafts). If a syntax or evaluation error occurs (eg. the domain specifies an unrecognized mechanism) the result is “PermError” (formerly “unknown”).” Examples:

   In SPF records