On Thu, 2004-08-26 at 16:14, Rand Wacker wrote:
On Thu, 26 Aug 2004, Jeff Macdonald wrote:
No. Both I and the people looking to implement these records feel quite
strongly that using the same record for both is very dangerous. In fact,
these largest sites are the ones who are *most* likely to have different
records (bit of a Catch 22 there).
Could you give an example? Or point to one is such an example exists?
Example of large sites that will have spfv1 records that would differ from
spfv2.0/pra? Sure:
Actually I meant "using the same record for both is very dangerous". I
suppose you mean hitting the UDP limits. But since you detailed the 2
records scenario I'm kinda confused.
<snip>complex bank scenario</snip>
Add to this the fact that these corporations regularly outsource marketing
and other material delivery to third party firms. Since they want these
messages to be branded as coming from their primary domain, the spv2.0/pra
record would include many include: statements like "include:esp1.com
include:esp2.com include:esp3.com" It doesn't take many additions here to
completely blow that 240 byte-ish limit that we're bumping up against by
inserting *two* records in one UDP response packet.
I'm sure there is a real concern about the size. However, these records
would be in the the Bank's primary domain space.
How would this differ from their spfv1 record? Well, since most
outsourced mailings use an ESP-controlled MAIL FROM address (for bounce
handling purposes), the spfv1 record would not necessarily include those
additional ESP references.
I think you meant the Bank's IPs listed (SPF2) in the Bank's primary
domain won't/shouldn't be listed in the ESP's spf records. However,
since the MAIL FROM is in the ESP's domain space, is this not a separate
DNS record anyway?
See my confusion? If MAIL FROM and Header FROM are different in the
domain portion that should mean that different DNS records need to be
looked up. I realize with Sender-ID doubles the amount of data. The SPF
and SPF2 records would indeed be different.
However, help me understand how the content of a SPF/SPF2 record could
be different if the MAIL FROM and the PRA have the same domain portion.
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