On Fri, Apr 02, 2004 at 12:06:53PM -0500, Stuart D. Gathman wrote:
| On Fri, 2 Apr 2004, Gordon Fecyk wrote:
|
| > I asked for a minimum specification for a recieving server looking
| > to receive the minimum benefit from SPF.
|
| Proposed minimal SPF implementations for mail receivers:
|
| Level 0:
|
| Check a subset of mechanisms: A, PTR, MX, ALL. Be sure that "unknown"
| results from an unrecognized mechanism. Do not support macros.
| Don't bother with Received-SPF. Note that no recursion is required for the
| minimal supported mechanisms.
|
| Level 1:
|
| Check recursive mechanisms and macros: INCLUDE, EXISTS. Add Received-SPF
| headers, for inspection by downstream software (e.g. bayesian filters will
| learn to use SPF results other than 'fail', including 'neutral' and
| 'softfail', in recognizing spam). Reject mail giving a 'fail' result with
code
| 551 and the recipient (allows the mail sender to bypass a non-SRS forwarder).
Both Level 0 and the INCLUDE and EXISTS parts of Level 1 would be
required fro a minimal implementation.
The specification is the minimal implementation. Where parsing and
interpreting are concerned, there are no optional parts.
Optional parts are denoted by MAY and SHOULD instead of MUST ---
Received-SPF, etc.
Please correct me if I'm wrong.