On Wed, 21 Jan 2009, alan wrote:
several have commented with all the v1 and v2 records in place and now a v3
on top
will add too much byteweight to the response to a query for UDP to handle
efficiently {or at all in some cases}
this is a serious issue {was my problem with spf originally as it broke my
standard of adding txt and rp records to most hosts
{now just rp pointing to a txt container}
so should we be considering a standard sub-zone for spf going forward?
no its simpler to fix than that
just recommend anyone doing more than 1 form of spf and/or sender-id
remembers about the issue and divides his records(s) appropriately
like thus
domain.tld IN SPF "v=spf1 redirect=_spf1.%{o}"
domain.tld IN SPF "v=spf3 redirect=_spf3.%{o}"
domain.tld IN TXT "v=spf1 redirect=_spf1.%{o}"
domain.tld IN TXT "spf2.0/mfrom,pra redirect=_spf2.%{o}"
domain.tld IN TXT "v=spf3 redirect=_spf3.%{o}"
That puts all that TXT data into a UDP packet - thus the "byteweight" problem.
One suggesting that *would* help is the standard subdomain:
_spf.domain.tld IN SPF "v=spf3 ..."
--
Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
Business Management Systems Inc. Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.
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