Andy Cowles writes:
> Hi There,
>
> I have an installation of Qmail that has been working fine with lots of
> domain names and user accounts... I now have one user who says that they are
> unable to receive email... they have tried sending themself a message from
> their AOL account and I get this message in my log maillog file;
>
> Dec 29 13:56:35 saturn qmail: 914939795.265747 delivery 57214:deferral:
> Connected_to_198.81.16.36_but_sender_was_rejected./Remote_host_said:_450_<ri
> [EMAIL PROTECTED]>..._Sender_domain_not_found_in_DNS_(see_RFC_11
> 23,_sections_5.2.2_and_5.2.18)./
>
> Is this something at my end or AOL (or both) what can I do about it??
Hrm. It looks like you already have. You'll get this message if the
envelope sender is completely unusable -- that is, if the domain name
is not in the DNS. It's perfectly reasonable to reject such mail at
the SMTP port because you cannot reliably send a bounce message in the
event of non-delivery. I'm VERY surprised that qmail-smtpd doesn't do
such a check. Imagine this scenario:
o Admin misconfigures his host with a domain name that has no MX, A, or CNAME.
o User sends mail to an invalid username at a site running qmail.
o qmail-smtpd happily accepts the mail.
o qmail tries to deliver the mail; cannot; generates bounce message to sender.
o Bounce message bounces because sender domain not in DNS.
o email has been misdelivered to unrelated third party.
o This is a total privacy breach, an email disaster.
--
-russ nelson <[EMAIL PROTECTED]> http://crynwr.com/~nelson
Crynwr supports Open Source(tm) Software| PGPok | There is good evidence
521 Pleasant Valley Rd. | +1 315 268 1925 voice | that freedom is the
Potsdam, NY 13676-3213 | +1 315 268 9201 FAX | cause of world peace.
