On Mon, 29 Jan 2007, Stuart D. Gathman wrote:
On Mon, 29 Jan 2007, william(at)elan.net wrote:
Checking PTR allows to verify if the client is authorized to be
doing SMTP connections as far as owner of the ip space sees it.
This is pretty similar to EHLO/HELO check as it checks if an
SMTP client with specified HELO name is authorized to be using
specified ip address. Note that they are not equivalent.
So basically, you're saying that if an ISP is unable/unwilling to
set up rDNS,
If they did not setup rDNS name the check is not an issue - the
answer would be "neutral" (ok - its a bit of a dns issue as you
asked and got NX answer and NX can not be cached quite as well).
My preference would of course be that ISP actually specify what
their policy is (i.e. "v=spf1 -all" at the PTR name SPF record),
then at least you see that they are pro-active with advertising
it and they do know how to use DNS and setup PTR data.
then you can't send email, even when their AUP
explicitly says you can, because they are the IP owners, and
their refusal to setup rDNS says you are not authorized to send email.
I know they are ISPs that don't respond well to customer requests
but really its customer service issue more then anything else -
if they allow you to send email from static mail server on that ip
then it should be specified and clear that is the real server.
--
William Leibzon
Elan Networks
william(_at_)elan(_dot_)net
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