spf-discuss
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Re: Multiple TXT records

2003-12-30 12:21:02
matthew-list(_at_)bytemark(_dot_)co(_dot_)uk wrote:
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On Tuesday 30 December 2003 16:06, R. Scott Perry wrote:

  If multiple explanation TXT records are returned, they are
  concatenated in the order they were received.  Use of multiple TXT
  records is discouraged as DNS does not guarantee order.

I think if multiple TXT records are returned, all but the first should be
ignored.

The problem is that SPF is co-existing with other DNS records.  If you
already have a TXT record for your domain for some reason (quite a few
domains do), then multiple TXT records are necessary.


So how about we ignore all but the first TXT record which starts with the magic "v=spf1 ... " ? I just wanted to take out the need to concatenate arbitrary numbers of TXT records. If a domain wants to have really complicated rules, it should indicate them by asking clients to do an A lookup for the in-arpa IP representation using macros, and implement the complicated logic or detailed database using resources on its own hardware. Otherwise a domain owner can specify about 18 IPv4 ranges or 8-9 IPv6 ranges and still fit within a 512 byte packet.

Aren't the "explanation TXT records" the macro-expanded strings used for the explanation text when a server denies an email on the basis of the SPF result? Those strings do not contain a v=spf1 prefix, and are not a rule.

I believe the current discussion relates more to section 2.1 (and not 3.5) which states:

  A domain MUST NOT return multiple records that begin with the word
   "v=spf1".  If more than one "v=spf1" record is returned, this
   constitutes a syntax error and the result is "unknown".

--Jonathan

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