On 10 Mar 2003, David Woodhouse wrote:
> Well, it's not _quite_ perfect but it's close. Going back to the
> example, if it transpired that 'anotherdomain' and 'yetanotherdomain'
> are both clients of the same hosting provider, and so the mail for both
> is in fact being sent to the _same_ remote host, Exim isn't going to
> notice that, and hence is still going to make two separate connections
> to the same machine.
Ahem. Exim is cleverer than you think. It notices identical host lists
that are generated from different domains. However, it doesn't try to be
more clever than that. For example, if you have:
dom1 MX 1 host1
MX 1 host2
dom2 MX 2 host2
MX 2 host1
it will use a single connection (yes, it spots the different order for
identical MX values). But if you have
dom1 MX 1 host1
MX 1 host2
dom2 MX 2 host1
MX 2 host3
it concludes that the host lists are different.
> And as Phil just said -- other MTAs won't necessarily be as efficient,
> although I think most should.
qmail makes a virtue of delivering each address in a separate
connection, as I understand it.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
