On Thu, Jan 22, 2009 at 12:57:30PM +0100, Schilling, Timo wrote:
> Hello to everybody,
>
> while we use the option "reject_unknown_helo_hostname" we noticed, that
> single hostnames will be rejected without contacting the dns-servers.
> After some debugging of the source code we got to this line:
>
> 226 _res.options &= ~saved_options;
>
> where the flag "RES_DEFNAMES" will be negated and so no
> domain-information will be added to the hostname.
The hostname is used with the HELO command in SMTP is required to be
the full hostname of the client not a leading prefix. If the hostname
is really just a single label as in:
ai. 14388 IN A 209.59.119.34
ai. 14388 IN MX 10 mail.offshore.ai.
Then it can use "HELO ai" and will pass the "reject_unknown_helo_hostname"
test.
Whether TLDs as hosts or mail domains are a good idea, is not a discussion
I want to repeat here, too badly bruised from the one just dying down
on another list.
Summary: FWIW, I believe that ICANN's gTLD expansion is a terrible,
perhaps even irresponsible idea, and the changes in RFC 5321 to support
<localp...@tld> email addresses is not well thought out. I hope such
addresses never come into serious use.
The folks arguing stridently against me also think ICANNs policy is a
bad idea, but believe that "progress" in this direction is inevitable,
and that it is OK to implement unreliable behaviour provided it is right
"most of the time", and so want to see <localp...@tld> work when the TLD
is known to exist, and to be treated as a local partial name otherwise.
This "have your cake and eat it" requirement has no reliable
implementation that does the right thing when DNS lookups tempfail. It
also has no sensible implementation in disconnected environments, ...
The above is just for the record. I *really* don't want to start a
discussion of the merits here. Time will tell whether Postfix needs
to adapt to a world with mail-enabled TLD domains and/or hosts.
--
Viktor.
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