On Oct 6, 2011, at 2:13 AM, Hector wrote:
Keith Moore wrote:
Right, but this mechanism is not stupid, instead it is clever ;-)
nope. it makes no sense whatsoever. it is using a completely irrelevant
test to decide whether mail is legitimate. and it's easily defeated by
spammers. it's not only a complete waste of time, it's worse in that it
causes legitimate mail to be dropped.
or at least initially cause transactions to be rejected at specifics
receivers doing IP PTR checking.
rejecting mail for this reason should be a criminal offense.
IMO, if the ISP is providing the name servers for a business tier account and
they fail to add ARPA records for the IPs, I would consider this MAL-PRACTICE
today - certainly tortious interference.
IMO, if an ISP is providing name servers for any customer and they mess with
that customers PTR records without specific direction from that customer, that
should be considered fraud on the part of the ISP. Whether those records are
populated, and what goes in those that are populated, should be determined by
the party to whom those IP addresses are assigned.
It's ridiculous to put in meaningless PTR records (the kind that just have an
IP address embedded in them) just so that stupid filters that check for the
existence of PTR records will think they're valid. It just gives more
appearance of credibility to a check that never was meaningful in the first
He got that resolved, but today, if you want to setup an MTA to send out
mail, you have no choice but to make sure the machine IP has an PTR record.
... and to kiss the assess of the RBL operators, and to pay tribute in any
number of other arbitrary ways to others who threaten to sabotage your outgoing