Bug#271564: 271564: Fwd: Mail delivery failed: returning message to sender

[Andreas Metzler]

On 2004-09-15 Mike Mestnik <cheako911@yahoo.com> wrote:
[...]
> Here is what I get from DNS...
> train:~# host -t MX filbert.is-a-geek.org
> Host filbert.is-a-geek.org not found: 3(NXDOMAIN)
> train:~# host filbert.is-a-geek.org
> filbert.is-a-geek.org has address 10.0.0.20
[...]
> R: dnslookup_relay_to_domains for cheako@filbert.is-a-geek.org
> calling dnslookup_relay_to_domains router
> dnslookup_relay_to_domains router called for cheako@filbert.is-a-geek.org
>   domain = filbert.is-a-geek.org
> DNS lookup of filbert.is-a-geek.org (MX) gave HOST_NOT_FOUND
> returning DNS_NOMATCH
> dnslookup_relay_to_domains router declined for
[...]

Running the same test on the internet against the public records of
filbert.is-a-geek.org, which have the same configuration, i.e. there
is a A-record but no MX shows this:

------------------
ametzler@downhill:~$ host -t mx filbert.is-a-geek.org
ametzler@downhill:~$ host filbert.is-a-geek.org
filbert.is-a-geek.org has address 24.245.9.227
downhill:~$ exim4 -bt -d cheako@filbert.is-a-geek.org
[...]
R: dnslookup for cheako@filbert.is-a-geek.org
calling dnslookup router
dnslookup router called for cheako@filbert.is-a-geek.org
  domain = filbert.is-a-geek.org
DNS lookup of filbert.is-a-geek.org (MX) gave NO_DATA
returning DNS_NODATA
DNS lookup of filbert.is-a-geek.org (AAAA) gave NO_DATA
returning DNS_NODATA
DNS lookup of filbert.is-a-geek.org (A) succeeded
------------------

It is using a different router dnslookup instead of
dnslookup_relay_to_domains but this does not matter,
dnslookup_relay_to_domains is essentially the same, just a litlle bit
more forgiving.

The real difference is HOST_NOT_FOUND versus NO_DATA, which is the
error given by gethostbyname(3). I am not very knowledgeable on DNS,
but I think dnsmasq is buggy in this respect.
               cu andreas
-- 
"See, I told you they'd listen to Reason," [SPOILER] Svfurlr fnlf,
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Neal Stephenson in "Snow Crash"