-----Original Message-----
From: Hector Santos [mailto:spf-discuss(_at_)winserver(_dot_)com]
Sent: woensdag 23 november 2005 22:15
To: spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
Subject: Re: [spf-discuss] Re: SPF adoption statistics
* Find sender host name by gethostbyaddr()
Checking the validity of an HELO/EHLO name has nothing to do with getting
a sender host name: by gethostbyaddr(), or otherwise.
And setting the HELO/EHLO name, based on gethostbyaddr(), is still wrong
when it gives you "hdev1" for a name, no matter what the cause. Indeed, as
a mail operator, you're better off just 'hard-coding' the HELO/EHLO name;
which is to say, sendmail offers you places to set the name manually, so
I'm sure Exim or PostFix offer similar configurability. But the sendmail
folks always consistently say: just fix the underlying problem so that
your setup does not need hard intervention. And I agree.
So as I said, as EXIM learned by release 4.30, it is better to do a di-
rect DNS lookup first because quote "it turns out that that is the only
guaranteed way to find all the aliases on some systems." and it goes on
to say, gethostbyaddr() works differently for various flavors of Unix.
Now, the reality about gethostbyaddr() is that it all depends on the OS
networking style (TCP/IP or NETBIOS or other) and HOSTS file. It has
nothing to do with WINDOZE or Unix system. Lots of software still use
the legacy methods, and even if the software was updated, there is no
urgent need to upgrade for this reason only because 99.99% of the sys-
tems do not REJECT on a HELO A record mismatch.
Nobody ever suggested a HELO/EHLO name should match a client's PTR or
anything. But people have been saying, me included, that your HELO/EHLO
name be a FQDN (or an address literal), and that an A record must exist
for that FQDN. So, "HELO hdev1" for an outgoing mail server, whatever the
obscure cause, remains dead wrong.
Now, also, I am not real happy with the sharpness of my tone in my last
posts to you. So, I will make this my last installment in this series. But
please do understand, that you cannot, within reason, expect me or others
to accommodate you regarding either a brokenness caused by your mail
software, or a misconfiguration on your part. At the end of the day, you,
the mail operator, are responsible for what you send out, HELO/EHLO wise.
And if it arrives here, in non RFC compliant form, as "HELO hdev1", then I
reserve the right to reject on that, without further ado.
- Mark
System Administrator Asarian-host.org
---
"If you were supposed to understand it,
we wouldn't call it code." - FedEx
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