On Wed, 21 Jan 1998, Jon Morby wrote:
> According to the manual,
>
> . bydns_mx: look up MX records for the host(s) in the DNS; fail if
> there |
> are none.
>
> Which I took to be that if no MX record exists, bounce the message.
The manual is correct, except that it doesn't say what it means by
"fail".
This is some unstated background philosophy. My design of the domainlist
router was under the belief that it would be used for special cases when
managers knew exactly where to send mail for specific domains. "If it's
for domain X, send it to host Y." Consequently, if it can't find host Y
it gets panicky.
You, OTOH, want something that says "If it's for domain X, try host Y,
but if you can't find it, give up". Is that right? It doesn't quite seem
to fit with your statement
We have a smarthost which should only relay for a certain set of
domains, or IP addresses. If mail comes in for a certain domain which
matches in mx_hosts then it should be forwarded to one of the hosts
which know about that 'internal' domain, hence the bydns_mx.
because that sounds as though once you have matched the domain, there
should be a host available. I think I'm missing something here.
> demon.co.uk has (today) c. 220,000 entries, and as such it's not viable
> to include as a table, and besides which we're using the DNS as the
> authorative record.
Hmm. Is it that you want to say "if this domain has an MX record" then
handle it with this router? The next release of Exim has an experimental
DNS lookup method, though at the moment it only looks up TXT records.
Maybe something could be done with that. [I wonder also if the
mx_domains option of lookuphost could help.]
Got to go to a lunch appointment. Back later.
Philip
--
Philip Hazel University Computing Service,
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P.Hazel@??? England. Phone: +44 1223 334714
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