Leonard Mills [Leonard_Mills(_at_)corpnet(_dot_)sel(_dot_)sony(_dot_)com] wrote:
It's quite useful for debugging purposes to know the one true name of
the SMTP server.
Although some hosts only have a single name, a "one true name" of a host
doesn't generally exist.
What is the "one true name" of 195.30.85.225? Is it "mehnle.net",
"www.mehnle.net", "mail.mehnle.net", "mehnle.de", "www.mehnle.de",
"mail.mehnle.de", or what?
If you say "io.link-m.de" because this is where the PTR of 195.30.85.225
points, does that mean I must use exactly that in my HELO?
Consider the case of a farm of servers sitting behind a BigIP load
balancer. To the outside world, it's a single IP, but those who can see
the one true name can tell which of those servers is broken or
mishandling their email.
I would not like to give that up to save a lookup.
Apparently you have not read my message thoroughly. I have not said that
I want Hotmail and Yahoo to say "HELO domain" instead of "HELO mx.domain",
although it might be worth noting that Hotmail already does exactly that
("HELO hotmail.com"). What I said was:
| [...] _if_ "domain" already is a hostname for the MTA (or can be made so
| without problems), then the MTA should say "HELO domain" instead of
| "HELO mx.domain". The prerequisite is already satisfied for many small
| sites.
This forces no one to say "HELO domain" who does not want to. It is a
simple recommendation for sites that can easily satisfy the prerequisite.