On Mon, 19 Dec 2016 13:09:22 +0100 Vincent Lefevre <[email protected]> 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
