On Fri, 27 May 2005, John A. Martin wrote:
william> ptr - DNS name for PTR pointer for SMTP Client IP address
And if there is more than one ptr?
Any one of them where 'A' (or 'AAAA') correctly matches smtp client ip,
otherwise none. I'm well aware that multiple ptr can be a problem (mostly
to the people who have set it up and have to administer this complexity),
but at the same time its rather rare right now and nobody is encoraging it.
PTR is an identity I proposed to use for MTAMARK-like verification on if
client itself is allowed to send email. You can do it directly with records
in in-addr of course, but idea was to move this to domain tld tree (like it
is done for all other SPF identities), plus not require extra lookup for
majority of legitimate mail systems (which have dns PTR name set to the
system name they would use in EHLO).
How about client IP (not necessarilly the same as any other)?
Not sure what you mean.
How about IP for DNS host in helo?
That would be covered under helo identity unless you have some special
idea about this and can explain why it would be separate identity.
--
William Leibzon
Elan Networks
william(_at_)elan(_dot_)net