On Wed, 6 Mar 2002, Ollie Cook wrote:
> Well hopefully all the lowest MXs would either all give 2xx, all 4xx or
> all 5xx depending on the recipient addresses in question.
Er, Exim has to operate in the _real_ world... :-)
> If Exim fails to connect to all hosts (or put another way, gets non-SMTP
> errors while connecting to all the hosts), then that to my mind is a
> different kind of error than getting 4xx errors from all the hosts.
Indeed. I think that that is the only possible clean specification. In
other words, distinguish between "all hosts uncontactable" and "any
other temporary error state", where the latter would include "some hosts
uncontactable, some gave 4xx" as well as "all gave 4xx".
> In the situation where the primaries are cut off from the network for a
> sizeable length of time (hopefully this would never happen, but I do like to
> plan for such occurances!), I would rather hold onto the messages myself on the
> backup, rather than rely on other ISPs which might have a very short set of
> retries before giving up.
I agree on the desired end, but I'm being cautious about specifying the
means.
> I'm interested to know what you mean by it being "safest".
Easiest to explain. Easiest not to get wrong.
> verify = recipient/callout=5s/callout_cannot_connect_ok ?
The syntax is the easy part. :-)
> Thank you for thinking about it, though.
Note that my next project is to get the 2nd Edition of the book out.
This means I'll only be working on the code (a) to fix bugs and (b) to
escape from working on the book from time to time. :-)
Philip
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
