running debian etch, exim4; running exim as a relay to an internal email server; no local [to debian] mail or users.
I know that I want a que, because if my internal email server is down, I want exim to collect & hold Email for it. Otherwise, I want email sent to it immediately.
Apparently, the que is not used for "local" delivery, and is only used to send Email on to its final destination.
So, in my application, I expect that ALL deliverable Email is placed in the que.
I read that there is immediate email delivery, and that some Email is "queued", and delivered when the que processes it.
1) Is any mail sent to the que delivered "immediately"? * If not, then all email is then dependent on que timing - yes?
There appear to be 2 variables responsible for when stuff leaves the que; /etc/default/exim4 & the retry section of /etc/exim4/exim4.conf.
2) does stuff leave the que ONLY when "it is 'run'* "?* if yes, then by default, email will only leave the que every 30 minutes [minimum] (QUEUEINTERVAL='30m' is the installed setting)
So* If this is correct, then I, personally, want Email leaving 'immediately'. So is there any reason I should NOT set queueinterval=1m ??
3) I can run a combined or separate daemon's for the que & smtp listening. For MY application - would I be better off with separate daemons?
/etc/exim4/exim4.conf - retry section
4) by default, the retry section waits 15min before attempting to re-send failed email. Is there any reason I should NOT set this to 1 min. ??* (unless my internal server is down altogether, this should only happen if my internal server has too many connections - a problem that could resolve itself in SECONDS, not minutes).
I hope that my questions are all clear...
TIA - Bob