spf-discuss
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Re: what to do upon syntax error?

2003-10-24 10:58:12

quick question: will a single TXT query return *all* TXT records for that
query?   Or will it require resolver-level iteration?
I'd be concerned about number of queries required, in the case of the
latter.  But as far as I can see it's the former.

A DNS server should return all TXT records.

However, there is a unique case where it will not: If the DNS packet would be over 512 bytes, the DNS server should fill in as much as it can, with the truncated bit set (instructing the DNS resolver to try again with TCP). In this case, the DNS resolver *should* switch to TCP, but anti-spam software may use DNS engines without this ability.

Yes, I was asking with regard to things like

jmason.org. IN TXT "if case of zone brokenness, ring +353-1-1010101, or email <jm(_at_)example(_dot_)com>"
  jmason.org.   IN TXT  "v=spf1 ...."

This -- at least at one stage -- was an informal convention, for providing
zone support data and comments, if I recall correctly.

There are quite a few domains with TXT records already in existence. I checked 1,800 domains that sent mail to us yesterday, and about 30 had non-SPF TXT records.
                                       -Scott

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