spf-discuss
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Re: improving Received-SPF

2004-01-08 17:37:40
Philip Gladstone wrote:


Jim Ramsay wrote:

Philip Gladstone wrote:

I think that smtp-receiver-hostname ought to be renamed to smtp-sender-helo

I think that's a better name... or did I mess up and put the wrong comment. Maybe it should be the hostname of the host computer?

I think it ought to be the HELO string -- it enables you to work out what all the macros expand to, and hence what the exact query was that was successful.

I don't know the exact rationale behind what it says now in the draft RFC, but I agree that the HELO is more useful than the current hostname which is quite obvious from other information already in headers.

We already have the hostname in the adjacent received line. Is there a statement that indicates that the received-spf line should be added at the toip of the email?

To me it looks like this line appears wherever it wants, but I don't know a lot about that.

Here is another updated definition. I was thinking about IPV6 addresses, and decided maybe the ":" delimiter between informational fields in the comment were not appropriate as IPV6 is commonly notated using ':'. How do people feel about pipe characters '|'?

header = 'Received-SPF:' result [ FWS '(' comment ')' ] CRLF

FWS = [*WSP CRLF] 1*WSP

result = 'pass' / 'fail' / 'error' / 'unknown'
         / unknown-declarations

unknown-declarations = 'unknown' *( FWS declaration )

comment = smtp-receiver-hostname '|' envelope-sender '|' current-domain
          '|' match-mechanism [ '|' comment-string ]

smtp-sender-helo = dot-atom-text
    ;dot-atom-text is defined in RFC 2822 section 3.2.4
    ;hostname given by SMTP client at HELO or EHLO command

envelope-sender = dot-atom-text '@' dot-atom-text
    ;dot-atom-text is defined in RFC 2822 section 3.2.4
    ;reverse-path given by SMTP client at MAIL FROM command

current-domain = IPV4Address / IPV6Address
    ;IP address of current SMTP client

IPV4Address = 1*3DIGIT 3( '.' 1*3DIGIT )

IPV6Address = 1*4HEXDIG 7( ':' 1*4HEXDIG )

match-mechanism = mechanism / 'none'
    ;mechanism format specified in section 3.2
    ;MUST be the mechanism (and argument) record checked which was
    ; matched to cause the result, copied exactly from the actual
    ; SPF record.
    ;MUST be 'none' if no match was made for any reason
    ;  (ie, error, no SPF information given)

comment-string = *( [FWS] ccontent ) [FWS]
    ;ccontent is defined in RFC 2822 section 3.2.3
    ;SHOULD include further information not already provided
    ;  (ie, description of error message in the case of errors)
    ;SHOULD mention if the "best_guess" function is used
    ;MAY include a human-readable explanation of why the current result
    ;  was decided
    ;MAY in the future include other "important" information such as SPF
    ;  version number, or additional colon-delimited information

Examples:

Received-SPF: pass (smtp.example.com|foo(_at_)example(_dot_)com|192.168.0.1|a)

Received-SPF: fail
 (smtp.bad.dom|aoeu1234(_at_)bad(_dot_)dom|192.168.0.2|-all|Sender not allowed)

Received-SPF: error
 (smtp.example.com|foo(_at_)example(_dot_)com|FF80:0:0:0:0:0:0:1|none|DNS lookup
 error)

Received-SPF: pass
 
(smtp.example.net|foo(_at_)example(_dot_)net|192.168.0.3|ptr:example.com|A-Okay)

Received-SPF: pass
 (smtp.example.org|foo(_at_)example(_dot_)org|192.168.0.4|none|Matched 
best_guess
 default)

--
Jim Ramsay

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