Re: best practices for fighting spam with Debian?
On Mon, 19 Dec 2016 13:09:22 +0100
Vincent Lefevre <vincent@vinc17.net> wrote:
> On 2016-12-16 17:58:26 +0000, Joe wrote:
> > It is therefore an important matter that the email admin ensures
> > that the PTR record *always* resolves to a hostname which resolves
> > back, which can if necessary be achieved by creating a fictitious A
> > record for just this purpose. It is not necessary for this hostname
> > to match either HELO or domain MX, though it's worth doing if that
> > isn't difficult.
>
> But you need to hope that the nameserver is compliant and
> in particular, won't truncate the list of IP addresses as
> with: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=834098
>
> > This check used to be pretty much a guarantee of a business IP
> > address, but unfortunately many home ISP accounts now have
> > complementary A-PTR records, making spam detection much harder.
>
> Their users may need to send mail after all.
>
Which they can do through their email provider, or more likely, through
webmail, without any PTR record at all.
Running a SMTP server on the Net requires a small amount of knowledge
and carries a certain amount of responsibility, which cannot reasonably
be expected of home users.
--
Joe
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