On Thu, 29 Jan 1998, Daniel Ryde wrote:
> I have problem with the "sender_verify = true" option in exim.
> I get numerious rejects from addresses like:
>
> 1998-01-28 08:00:18 0xxRTu-0000z3-00 rejected from (weather.skiinfo.no)
> [195.159.50.19]: temporarily unable to verify sender address (try again later)
> <bolav@???>
> ...
> $ host -t mx weather.skiinfo.no
> weather.skiinfo.no MX record currently not present
> $ host -t a weather.skiinfo.no
> weather.skiinfo.no A 195.159.50.19
>
>
> 1998-01-28 08:42:43 0xxS8x-0001Ol-00 rejected from (minivend.booktraders.com)
> [207.207.142.59]: temporarily unable to verify sender address (try again
> later) <owner-minivend-users@???>
> ...
> $ host -t mx minivend.com
> minivend.com MX record currently not present
> $ host -t a minivend.com
> minivend.com A 207.207.144.67
>
>
> They have a perfectly valid A record but no MX. Are there supposed to be
> rejected using "sender_verify = true"?
That looks like a DNS error. Notice the "record currently not present".
That is not the same as "has no MX record", which is what you get when
the DNS resolver gives a positive negative reply, if you see what I
mean. Exim cannot discover whether there is an MX record or not.
Consequently, it cannot go on to look for an A record. It treats this as
a temporary error. Hence the message "temporarily unable to verify"; the
error it gives back to the sending host is a temporary one (4xx).
There is something really odd about weather.skiinfo.no. If you look up
an MX for xxx.skiinfo.no you get the MX record
xxx.skiinfo.no. 86400 MX 10 mail.skiinfo.no.
This is true for yyy, zzz, w, we, wea, weat, weath, and weathe, but not
for "weather". I suspect there is a wildcard MX that is matching all
those, but there is a broken MX record for "weather". Hmm. I've just
pulled the whole domain, and there is the wild card, but the only
entry for "weather" is the A record.
*.skiinfo.no. 86400 MX 10 mail.skiinfo.no.
weather.skiinfo.no. 86400 A 195.159.50.19
I now suspect a bug in their nameserver.
BUT WAIT: Exim on my host can verify that address:
ursa$ exim -v -bv x@???
x@???
remote delivery to x@???
host weather.skiinfo.no [195.159.50.19]
ursa$
Is it still going wrong on your host?
--
Philip Hazel University Computing Service,
ph10@??? New Museums Site, Cambridge CB2 3QG,
P.Hazel@??? England. Phone: +44 1223 334714
--
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